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Mark Anson
Prolific User Username: bentleybloke
Post Number: 90 Registered: 11-2004
| Posted on Monday, 08 May, 2006 - 00:56: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Hi All, I have just replaced all eight brake shoes on my Mk VI and now have hardly any brakes! I appreciate the shoes will take some time to bed in but I wonder if something else is not right too. The reason I thought I would renew the brakes was they needed to be stood on to work. I am about to go back outside and have a look at the servo and linkage. Whilst looking at the braking system I wondered how hard would it be to convert the system to hydraulics. You could use a clutch slave cylinder or something similar and connect it to the rear brake rod. The servo could be disconnected. A new master cylinder could be fitted off a modern car. To give extra help with braking a remote vacuum servo connected to the inlet manifold could work. Any thoughts on this? Has anybody done something similar? |
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Richard Treacy
Grand Master Username: richard_treacy
Post Number: 995 Registered: 4-2003
| Posted on Monday, 08 May, 2006 - 02:42: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
You could perhaps fix the brakes properly so that they work as they should (brilliantly by modern standards). On the otherhand, you could also scrap the car and buy a new Ford. |
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Mark Anson
Prolific User Username: bentleybloke
Post Number: 91 Registered: 11-2004
| Posted on Monday, 08 May, 2006 - 07:05: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Richard, Thats just it! as far as I am aware I have fixed them how they should. Using a genuine Mk VI workshop manual I have adjusted the rods as recommended and still the pedal has lots of travel and the brakes hardly work. I have just adjusted the servo again and that has improved them slightly whilst moving in gear but still the rear brakes don't seem to be working fully. If I pull the handbrake on whilst driving the car will slow. If I press the footbrake it wont (unless I stand on it). If I depress the clutch at the same time (disengaging the servo) the car just coasts along with no braking at all. When I removed the worn shoes I disconnected the linkage to the rear brakes (rod A). The equalizer arm sprung right back as if the rod had been adjusted so much it was holding the brake on. I wonder if a previous owner has done this to overcome some wear somewhere. I am unable to get the arm into the same position as I found it as the extra thickness of the new brake lining has taken up all that slack and the brakes would come fully on. The manual says put some tension on the rear brake rod to stop any rattles but there is not much free play in the shoes at all. All adjusters or right off, both brake expanders are fully off too. When I pull the rod manually the rear brakes work fine. I will try and get the car on the ramp at work with someone sat in it operating the pedal just to see what is moving. Will report back. Any suggestions as what to look out for? Thanks Mark
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Bill Coburn
Moderator Username: bill_coburn
Post Number: 644 Registered: 4-2003
| Posted on Monday, 08 May, 2006 - 08:24: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Sorry Mark but Richard's cynical rejoinder was only mild to what I felt when I read your 'proposal'. The brakes are excelent on these cars and to modify them as you suggest would not only probably destroy the car, but you would never get it registered. Anyway, now that I have got that off my chest I'll try and offer some helpful approaches. The back brakes first of all provide the smaller proportion of the total braking effort so I would be wondering where the front unit effort was. These cars are now very old and strange things are happening to them. The brake lines are steel and subject to rust. In addition the flexible lines if they haven't been replaced will have detached their linings and are probably jammed up. So step one is to check that fluid is getting through but surely this would show up when you bled the brakes. You did replace all the rubbers and overhauled the master cylinder I presume? Lets be assured that you have verified these things and then get back. |
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Mark Anson
Prolific User Username: bentleybloke
Post Number: 92 Registered: 11-2004
| Posted on Tuesday, 09 May, 2006 - 05:09: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Thanks for your post Bill. To answer your question no I have not serviced the master cylinder etc. My main concern was all the brake shoes were nearly worn down to the rivets. I removed the shoes (marking each one) and had new original linings riveted on by a brake specialist. I then fitted them to the car. It is since then the brakes have become worse. I think my main problem is the linkages so I will have to spend a bit of time working out how they operate and see if anything is amiss. I will also check the hydraulics. Thanks Mark |
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Marty Unregistered guest Posted From: 220.237.114.69
| Posted on Wednesday, 10 May, 2006 - 21:07: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Gidday Mark, Brakes on my MK VI are excellent, brakes on my mate Rob's R Type were pretty woeful. You have to stand on the pedal to get anything happening. One big improvement I found was an oil leak onto the linings of the clutch for the servo. If the servo clutch is not biting, you loose all of the benefit of the servo. Take the servo apart, and look at that. Check for oil leaks from the gearbox. Flexible front hoses are cheap as chips, same fittings as for many standard pommie cars, I think I paid $40AUS for the pair. Worth while changing. With age the inner part of the hose collapses, not good. Brake fluid should be changed every 2 years as it absorbs water (hydroscopic) and this will rust out your master cylinder and wheel cylinders. A good dot 4 brake fluid is fine, rated to 525 degrees F is pretty standard. I have seen a servo shaft which was actually broken, not sure what happened, but glad I wasn't driving the car at the time! My Mk VI stops twice as well as my MG Magnette, and would even give a modern ABS car a run for it's money on a dry road. My 1925 Dodge on the other hand, has externally contracting rear brakes only, slowing is possible, stopping? I'll get back to you! Good luck Marty
(Message approved by david_gore) |
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Bill Vatter
Frequent User Username: bill_vatter
Post Number: 23 Registered: 9-2004
| Posted on Monday, 15 May, 2006 - 20:03: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Mark, Your post of May 8 indicates you do not understand how the brakes work. You said, "If I depress the clutch at the same time (disengaging the servo) the car just coasts along with no braking at all." The clutch has no effect whatsoever on the brakes. The symptoms you describe indicate that either (1) the servo is not working, or (2) the hydraulic system is not working. Loss of fluid in the hydraulic system will render the front brakes completely inoperative. If you have no brakes at all ("just coasts along with no braking at all") there is something wrong in the linkage going to the rear wheels, or possibly you did not put the rear brakes together correctly. When assembled correctly, the pedal is directly connected to the rear brakes, and even if the hydraulics and servo are not working, you should get something, albiet not much, when you push the pedal. Also, a word of warning: When you replace the front brake shoe linings, you need to check out the front brake cylinders. If they are original, they will have to be rebuilt or they will begin to leak very soon. This is because the rubber piston cup(s) will be running against a different place inside the cylinder, and this different place is probably rough from corrosion. Possibly if the cylinders have been sleeved with stainless steel or brass, they will be OK. If not, you will need to sleeve the cylinders and replace the rubber parts. Mark, you should invite someone over to look at your car and advise you. Someone from your local club who understands the car. In the clubs there are people who will know what is wrong. I perceive you are in the UK. Are you a member of RREC or BDC? If not, that is your fundamental problem.
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Laurie Fox
Experienced User Username: laurie_fox
Post Number: 19 Registered: 6-2004
| Posted on Monday, 15 May, 2006 - 23:51: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Mark I am surprised that you are asking all these brakes questions again. May I remind you that about two years ago your queries on the BDC Bulletin Board resulted in much information being provided on brakes and other matters. I also sent you a file containing all the official brake information. That BDC Bulletin Board has now been superseded with a later one but I transferred all the technical information into the archives section of the new board where it is still available in the MK VI, R Type and S1 forum, in topic MK VI Carbs running rich. Here is a copy of the posts in that topic. "Posted: Fri Jun 18, 2004 10:54 pm Post subject: Mk VI Carbs running rich -------------------------------------------------------------------------------- markatmirage User posted 02-05-2004 01:47 PM Hi All, Just bought my first Bentley yesterday! Having a little tinker and found the enagine is running really rich. I have tried adjusting the mixture but the carbs dont seem to respond. I would like to buy a manual but dont seem to be able to find one. Anyone selling one? Is there a common fault with these SU carbs that make the engine run rich? I am a bit worried as the engine oil smells of petrol so its not doing my engine much good. Is there a website that has information on setting up the carbs? How easy is it to obtain service kits for these carbs and were is the best place to buy? Sorry for all the questions but I am dying to get the car out on the road there is only so much polishing you can do. Thanking you in advance Laurie Fox User posted 02-05-2004 03:59 PM There is much information about your problem in the MK VI Workshop Manual which is available to members from the Club Office. Meanwhile, since this is a bank holiday week end and you may be keen to get the car going, I will suggest a few things and we can probably comment a bit further when we have your reaction. First of all, what is the chassis number? Are the carburetters bolted on to the induction manifold with two bolts each or four bolts each? Do the carburetters flood when the petrol pumps are switched on and the engine is cold and not running and, under these conditions, is there any ticking from the petrol pumps which would suggest a petrol leak somewhere? Can the mixture control on the steering column move the jets on each of the two carburetters up and down to the full extent? Has the richness suddenly appeared or was it there beforehand? Are the pistons in the carburetters free to move up and down without sticking - check by removing the oil cap on the top of each carburetter and lifting them with a pencil, or something, and pushing sideways while you lift. Whereabouts do you live? What did you do when you adjusted the mixture? ------------------ Laurie Fox [This message has been edited by Laurie Fox (edited 02-05-2004).] Ashley James User posted 02-05-2004 05:56 PM Make sure that the needle valves in the float chambers are sealing. Take the lids of the float chambers and invert them, a 7/16" drill should just slide under the lever that presses onto the floats. Shake floats to make sure they have not got fuel in them. If they have replace them. Disconnect choke linkage and screw jets up as high as they will go, then using a vernier depth gauge screw them down 35-38 thou. Mixture will be correct now but you need to establish that throttles are synchronised. When you put the choke linkage back on, make sure it does not alter jet position and that the steering wheel linkage is correctly adjusted. Make sure that vacuum pipe for windscreen washers is not leaking air and making the mixture weak once the jets are correctly set. www.burlen.co.uk Burlen Fuel Systems of Salisbury are the official SU agents and will supply any spares you may need as well as instruction sheets. If the needles in the float chambers need replacing, buy the special spanner from Burlen to avoid damage to the float lids. The Banjo bolts that retain the fuel unions to the lid of the float chambers are prone to loosening, a dab of loctite will hold them. There is a fuel filter near the petrol tank on the offside rear of the car. Make sure it is cleaned out and functioning properly. If dirt is getting into carbs, they will flood intermittently. Check that the fuel pumps are in good order and that there is a spark suppression diode accross coils. Any doubts, fit a new pump. SU fuel pumps come straight from hell! Best of luck. markatmirage User posted 03-05-2004 11:24 PM Hi Laurie and Ashley, thank you for your replies, lots of great information. I bought this car a four days ago and have not got used to its quirky ways yet. Some of the answers to your questions are here. Chassis number B72DA (can anyone tell me a little about this model?). Carbs are bolted on with two bolts. Carbs don't seem to flood when ignition/pump turned on (pump also stops ticking). Throttle control on steering wheel works as does the choke (whether it opens them fully or closes them I can't tell. Thought I might have to disconnect links to see how far they should move). The poor running has been since I owned it (four days) but I have found lots of receipts for carb parts (some the same parts!) which shows the previous owner has had problems in the past. The pistons appear free and full of oil. I live on the Wirral, ten miles from Liverpool over the Mersey. The only adjustments I made was turning the nut under the base of the carb, I presumed this would be the same as a mini as I have adjusted them in the past this way. I have not stripped the carbs down yet as I learnt with my Cadillac I own at the moment "Start with the basics and keep it simple" The washers are not connected and I cant find the pipes, the car is running so rich you don't need the choke on to start it. I will have to spend a little time messing with the carbs next weekend. Unfortunately the carbs are the least of my problems. I took the car out for a run (with the mother in law, wife and four year old daughter) got to the end of the road and the car did not stop. A transit swerved to miss us and mounted the kerb!!! The footbrake was hardly working. I took the car into the garage I work at and put it up on the ramp.Now the main reason I bought this car was to replace my Cadillac (for weddings) so the Bentley seemed ideal with its brand new MOT certificate (tested on the 20th April 04). Under the car I found the brake master cylinder leaking, a bolt missing from the n/s wheel cylinder, both front wheelcylinders seized and not working and the brake shoes worn just above the rivets. All these items are fails (and the windscreen washers too!) I have emailed the chap I bought it from and will speak to the MOT test station tomorrow. No doubt nothing will be done and I will have to cough up myself! Could you tell me were the best place is to buy brake parts? I was going to get 1 x master cylinder repair kit, 2 x wheel cylinder repair kits, 2 x front flexible brake hoses and front and rear brake shoes. How much do you think that little lot will cost? Cheers Mark Ashley James User posted 04-05-2004 09:22 AM Mark - you are very lucky, not far away in Stockport, is one of the best men in the country on MKVIs. Ring Norman Woolfenden on 07703203903 and explain that, in a round about way, I gave you the number. He is extraordinarily reasonably priced too. bensport Moderator posted 04-05-2004 07:55 PM Mark, If the brakes are like you say, then you must be prepared for more of the same. It is vital to have such purchases examined by someone that knows about the snags and faults that are common on these old Bentleys before you commit yourself. As you probably know you cannot test the brakes on a roller testing rig as the car must have the rear wheels rolling as well as the front due to the servo actuation by the propshaft. You need to use a Tapley meter. Let's hope that you do not find to many other major faults but I should get the experts on these cars, to look at the steering for the known danger points. Careful rebuilding and correct setup of the carbs will be fairly straight forward, they are very simple. Do keep asking if any help is needed on this website. bensport markatmirage User posted 04-05-2004 08:51 PM Hi Bensport, could you tell me if the front brakes will still work without the prop spinning? When I say this I mean like modern cars and the engine not running the servo does not assist the brakes and you have to press much harder on the pedal. The brakes do work though as the hydraulics work without servo assistance, is my Bentley the same? I tried to turn the front wheel with the footbrake on (car standing still and engine off) and both front wheels spun freely...surley this is not right? Do you think a Tapley meter will give a good reading with just the rear brakes working? Can you tell me if the rear brakes are hydraylic too? I have seen what just looks like rods going from the master cylinder to the back axle. Thanking you in advance. Mark Laurie Fox User posted 04-05-2004 10:18 PM Mark Several points re your last posts. First of all about the car generally. B72DA is fairly early in the D series and the series letters run alphabetically up to and beyond R. All of the pre R series are known as Mk VI`s and the later series are all known as R Types (irrespective of whether they are series R,S,T etc.). Over the years very many modifications were introduced and the Workshop Manual lists the more important ones (over 150 in all) and gives an indication as to the chassis number when each was introduced. The spare parts list gives information about which parts apply to the various different configurations and also gives part numbers for the Standard Steel Saloon body and for the different chassis parts which apply to the coachbuilt cars. However there are a few typing errors and in some cases better parts are now available from specialist firms, but the more information you have the better, so I strongly recommend that you get the spare parts list and the Workshop Manual if you intend seriously to get B72DA back into good condition. There is, in addition, a Service Handbook (A5 size) which augments the Workshop Manual to a useful extent. Broadly speaking the Workshop Manual is guidance to the fitters etc. whereas the Service Manual is more for the workshop supervisor. A copy of the original build sheet for the car is probably available from the BDC club office. Since you mention using the car for weddings I guess that the bodywork is in fairly good condition and that it is probably coachbuilt, but mechanically it does sound as though it has not been looked after very well. Engines get changed now and again and the Rolls standard practice of transferring the original engine number to any replacement means that the engine number is not a reliable guide as to whether the engine is the original engine or not. Look at the nuts on the cylinder head studs and see whether they are 5/16" or 3/8" (BSF in each case). Cars before about B95DZ had 5/16"studs to start with so if B72DA has 3/8" studs the engine may well be a replacement. My earlier point about the number of bolts holding the carburetters on relates to a modification to introduce larger bore carburetters round about the H series. If your engine does have 5/16" cylinder head studs then it may still have the original chrome flashed cylinder bores. Your experience with the brakes alarms me. The braking system is based on a mechanical servo scheme and you need to know what you are doing when dealing with it. There is full information in the Service Handbook Section G and, some time ago, I put this on a file which I can email to others. I will send this to you if you would like to have it and if your mailbox will take 7MB in one go. The reason for such a large file is that many years ago I lent Section G to some Austrian members and never got the 25 sheets back. Eventually I was able to replace them with photocopies but these photocopies are not good enough to scan for OCR text so my file is in .jpg format. If the 7MB is too big for you I will break it into smaller chunks. This will explain fully why there is no front wheel braking if the prop shaft is not going round. The rear brakes are rod operated and the front brakes are hydraulic. Regarding the windscreen washers there should be a holder for the water container somewhere. Mine (on B420EY) is on the bulkhead on the nearside but it may be different on other cars. Just above the water container is a small bore plastic pipe which goes through the bulkhead into a space which is difficult to get at and which may or may not contain filters as well as piping to the washer outlets. The standard washer drive is via a vacuum system (at least on the later cars) though mine had an electric drive when I bought it. You are right in screwing the bottom nuts on the carburetters up to weaken the mixture but you have to make sure that the spring return and the linkages do permit the jets to rise so that they touch the face of the nuts. But the threads get bunged up sometimes and the nuts do not go up as far as they should. There are no other mixture adjustments on the SU carburetters. ------------------ Laurie Fox bensport Moderator posted 04-05-2004 11:32 PM Mark, The brakes are hydraulic only at the front. They depend on the servo which is driven by the propshaft so when you are going very slowly they are not so efficient. The rear brakes have to be in good shape and correctly adjusted to operate the hydraulic ones at the front because the rods are pulling against the rear actuation for the pressure on the master cylinder. I will explain more in detail if you wish. No the brakes will not work, without the prop shaft turning, at the front. They will give a little on the backs as same as the handbrake. The Tapley meter will give a very good reading at 30 MPH if the brakes are in 100% perfect as designed working order. Like 80%; or better on some cars that are the well known Special Tourers. More explanation later. bensport bensport Moderator posted 05-05-2004 07:56 AM Hi! Mark, Although some things like the brakes can be time consuming to overhaul, as can most mechanical aspects of these superb Bentleys. It is the bodywork that can be terminal and uneconomic the repair. I hope you are not in that situation. The worst rot occurs to the sills, then the rear wheel arches and so on. Repairable yes, with patience and a competent welder. If too far gone then the body has to be removed and the chassis modified slightly to move the engine/trans back and possibly shortened on wheelbase to use all left for a nice open 2/4 seat tourer body. This has been done to hundreds of these cars. Anyhow, as you are now, the braking system works from the pedal to the servo which is mounted on the rear right side of the gearbox. This is a Ferodo actuated device by three 5/16 ball operated cams that engage the friction disc to pull the 2 brake rods that actuate the push rod into the the M/cyl.Via a balance lever ass. 2 rods required so that the whole device works in reverse gear too. The pedal pulls a rod that acts on the cams as said before but as an opposite force resistance to the pedal pull rod, another rod runs to the rear of the car through a cross shaft mechanism. In turn this second rod pulls on the rear brakes and is vital to the braking of hydraulic actuation at the front via the M/cyl. That is a simplification of it, I hope. You need to have a Workshop manual. These are sometimes available from the BDC which is a good club to be in as there are a large number of member's with Mk Vls. There is another manual that should be OK for you if available from the RREC club. This manual is for the early cars only but most of it will cover your model.It may still be avaialble but not sure if non members can buy it. Any further questions? Good luck, Bensport. markatmirage User posted 05-05-2004 09:29 PM Hi Bensport EEEKK! The brakes sound like a bit of hard work. I still cant get my head round the hydraulic part of the system. I am presuming that when you push the brake pedal down with the prop not spinning the rods would move and operate the rear shoes and the brake fluid would still push the front shoes/wheelcylinders...the servo (which is obviously not working whilst stationary) only provides assistance during vehicle movement. Am I wrong? No one has answered this yet. I am taking my Bentley to our local garage on Friday for another MOT, the garage who tested it the other week will carry out any repairs my garage finds. A bit of a pain but obviously the previous owners garage did not carry out a thorough test...perhaps it did not even go on the ramp!!! who knows. My garage will use the Tapley meter but I was going to put the front wheels in the rolling road brake tester and jack the rear wheels up so they can spin and turn the prop. This I hope will show how well the brakes are working on the front. Can you see any problems with this? (other than the car lurching out of the rollers. I did intend testing one wheel at a time to avoid this) Cheers Mark markatmirage User posted 05-05-2004 09:45 PM Sorry...forgot to say...bodywork is great (black over ivory). Chrome new (just done) Interior beige leather done 12 months ago. Wood not 100% but you cant have everything. Engine not long ago reconditioned, radiator recently done. Jobs that are outstanding, fuel gauge inoperative, temperature gauge coiled wire broken all ext door handles need chroming. Not sure if oiler system is working. Mark Ashley James User posted 06-05-2004 10:31 AM Pump oiler system until oil appears at rear nearside shackle. Quite often system is Ok but needs more pumps than you think. Mike Jones is a useful contact he breaks these cars and hold quite a lot of spares. 01789 400011 Eric Healey is the specialist on 01933 650247 Laurie Fox User posted 06-05-2004 02:06 PM Mark Thanks for your email. The brakes file will be sent within the next hour or so. All should be clear if you study this info. but let me know if there is anything which is not understandable. Meanwhile, just a little bit of explanation about the servo which may help. The servo consists essentially of two plates, one of which goes round, one way or the other when the car in moving, either forwards or backwards, and the other is pressed against it when you push on the brake pedal. This second plate will then tend to turn if the first plate is moving but not otherwise and if it does tend to turn then it pulls one or other of the two rods attached to it depending on which way it is being turned by the first plate. The rod which is being pulled (forward) pulls a swinging link assembly forward and the other rod moves so as not to impede the movement of the swinging link. The swinging link movement pushes a rod to apply force to the hydraulic master cylinder and thus to apply the front brakes and also pulls a rod which applies the rear brakes (indirectly). The rod from the swinging link which eventually applies the rear brakes goes to a shaft which does several things. One of the levers on this shaft is from the handbrake, one goes to the rear brakes actually to apply them and there is another rod which goes back to one of the servo cams. The other servo cam is connected to the brake pedal. The effect of all this is that in normal operation, when the system is correctly set and the car is moving either forwards or backwards, the application of the brake pedal moves the second plate towards the first and the second plate rotates to apply the brakes. There are clearances etc. in the mechanism which means that there is a small amount of play to be taken up in several places and this means that there can be about 9 inches or so of car movement before the braking action starts. This is of no consequence in normal driving but can catch you out if you are manoeuvering in a tight space and this is no problem once you are used to it. When the car is stopped and the servo is not rotating, pressure on the brake pedal does apply a slight pull on the rear brakes (through the servo cams, even if the servo is not going round) but since the car is still anyway this makes no difference. The reason why the few inches of movement before the brakes work are normally not noticeable is that it takes a certain amount of time to move the brake pedal with your foot from the rest position downwards and the car will usually travel more than the "slack" few inches before the servo closes. However a very quick pressing of the brake pedal at low speeds will engage the servo before the clearances have been taken up and the brakes will then come on suddenly quite hard. Once the clearances have been taken up there is a one to one relationship between the distance moved by the brake pedal and the movement of the rear brake expanders. As the brake linings wear so the brake pedal will go further down for a given degree of brake application and this is an indication that the brake adjusters (not the expanders) need resetting to compensate for wear. If there is no more movement possible in the adjusters then it is time to reline the brakes, but the rear adjusters can get stuck due to lack of lubrication etc. before they reach the end of their travel so it is worth while to make sure that they are free. Back to the swinging link again. The top of the swinging link merely pushes on the hydraulic master cylinder to create pressure for the front brakes. But the swinging link will have no movement unless the servo is going round and so you cannot test the front brakes with only the front wheels of a rolling road. Don`t try to put the front wheels on a rolling road with the rear wheels jacked up and the engine running - it is just too dangerous. Brake pedal travel gives no indication of front brake lining wear as it does in the case of the rear brakes but if you check the front adjusters and reset them whenever you do the back ones you won`t be far wrong. I am puzzled by the fact that your brakes are at present so ineffective. Sit in the car (car stopped, engine not running and handbrake off) and press the brake pedal. There will be a slight resistance when the servo plates become closed - how far down is the pedal at that point? If there is no servo closure resistance at all then check according the Service Handbook Section G straight away. From that point onwards there will be further movement until the rear expanders move the brake shoes into contact with drums - how much further do you have to go to reach that point? If the servo closes but you don`t reach the second resistance point then check that all the rods are there and check the adjusters on all four wheels. If you don`t find these two resistance points when pressing the brake pedal with your foot try pressing by hand to get a more sensitive feel. When you get the car to your second garage on Friday you could have the car up on a ramp with the rear wheels jacked up and, with the engine ticking over, actually see the various movements of the rods and everything with someone else in the driving seat - no need to put the brakes on hard, just enough to slow the engine slightly. When the braking system rods are correctly set certain stops come into action which result in the rear brakes still working if, say a front brake hose fails, or if a pin comes out of any of the rods near the rear brakes then the front brakes will still work. Assuming that the rod adjustments are reasonably OK then there is another check which will also indicate the need to look at the brake adjusters. This is to note how many "clicks" there are in the handbrake handle movement when you pull fairly hard. There should be somewhere between three and six clicks. Apart from the brakes and the rich mixture I would rate the radiator thermometer and the fuel gauge as the next most important matters, leaving the central chassis lubrication system until later. If the radiator thermometer feed wire is broken than that means replacement since repair is not really practicable. The non operation of the fuel gauge could be due to one of several causes and I can let you have some diagnostic checks to explore when you are ready to start looking at it. Both the radiator thermometer and the fuel gauge are in the left hand instrument cluster and there is a knack in getting access to them which I can tell you about provided your car is a standard steel saloon but if it is coachbuilt it may not be quite the same in the dashboard area. Meanwhile, when driving without a working radiator thermometer or fuel gauge, do be very careful re overheating - carry spare water and spare fuel in the boot in case you need them. ------------------ Laurie Fox bensport Moderator posted 06-05-2004 11:06 PM Thank you Laurie for another excellent reply to the question of the Mk Vl brakes. Your explanation is both simple and without any doubt as to the accuracy of it. Mark, You seem to be wondering about spare parts. There are other people in the UK that supply the official new parts. Jack Barclay are the people that are the Crewe Genuine Parts official supplier. www.jackbarclayparts.co.uk Every one else gets their supplies from this single source. There are other people that supply new/used parts and their adverts are in this Club's; BDC Advertising Magazines. bensport Ashley James User posted 07-05-2004 04:52 PM It is not true to say that all parts come through Jack Barclays. Both Healeys and Ristes have parts made that are less expensive and Brian Thompson and Theo Hendrickson have access to military B60 parts that are far less expensive. Mike Jones has quite a few parts made too. What is true is that Ricky Cooper, Barclays pre'55 parts man, is tremendously helpful and will often re-direct where he has a conscience over R-R's prices. It does pay to shop around bensport Moderator posted 09-05-2004 09:10 PM Ashley yes, you are quite correct that the other main Bentley dealers do supply parts for the later models than 1955. It was the 'Pre-1955' specific ones that the J.B.s were given the franchise for when Rolls-Royce changed from Appleyard's. Long may this continue, for unless you have the facilities to manufacture items such as the Manual Mk Vl/R gearbox internals, steering box ditto, rear axle ditto. and fully machined con rods and crankshafts etc.to the correct R-R specs, we may start to feel the pinch before long. The spares situation is of course the most important of all to us Club members in keeping our Bentleys on the road. The B series engine parts are available as you indicate but very few are exactly the same as the Mk Vl & R Type. Engine parts can be of a more basic un-polished not fully machined finish, as the passenger car specs are. So be careful. bensport. Giles Usher unregistered posted 11-05-2004 11:48 AM Firstly, with this new Mk 6 of yours, don't panic. Even the concours cars need things doing to them - they are like the Forth Bridge. I see that this car will be used for weddings. But I advise you not to do what some wedding car owners do i.e. the bare minimum to keep them on the road. The Mk 6 and R Type responds amazingly well to professional maintenance and can be a pest if all it has ever had is backstreet maintenance. Unless you know these cars well, entrust repairs and maintenance to someone who knows what they're talking about. Such as Norman Wolfenden, Ristes, Alpine Eagle etc. If the one shot central lube system has been all but forgotten, you will have problems with shackle pins drying out, king pins breaking up. If the system hasn't been used for ages its possibly gummed up with decaying EP80. The brake master cylinder is always an achilles heel. Great fun - because the fluid is hydroscopic if the car has been stood around, the cylinder rots. I had mine reconditioned with a brass cylinder which should hopefully outlive me now, plus many of the pipes renewed. Your servo might also be mucky - does the car have undertrays? Can you see the servo quite easily? You shouldn't be able to, in which case you have undertrays missing (essentially they are splashguards to keep the underside clean from road muck). There is a separate undertray and vertical shield to keep the servo clean and dry. Don't under any circumstances let some know it all convince you to abandon the one shot system and move over to grease nipples. I won't go into it here, as I'm in the office and should be working, but it does not work on a Mk 6 and will cause untold damage in the long run. What you really need to do at the outset is meet a few Mk 6 nutters like ourselves, put the car on ramps or blocks, and go over it in detail underneath from front to back, then go over the body, checking the sills are sound, that there is no filler, and that all body mountings are in place, at least the ones you can see. Once you have a shopping list of what needs doing first, you can then draw up a renewable 5-year plan like Stalin used to, and plan your budget. Make a start by making physical contact with BDC and RREC members and take it from there. This will frighten you into activity but should also provide some reassurance that the car is actually fairly sound all things considered." Regards Laurie
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Marty Unregistered guest Posted From: 211.30.119.17
| Posted on Saturday, 20 May, 2006 - 21:06: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Hey Mark, what did you find? Hope you don't have a wedding this weekend! Would be good to know what went wrong. Cheers Marty
(Message approved by david_gore) |
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Mark Anson
Yet to post message Username: mark_anson
Post Number: 1 Registered: 11-2006
| Posted on Sunday, 12 November, 2006 - 23:05: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Hello Folks, long time no speak. WOW...been off this site for several months now due to weddings etc. Cant believe the responses to my brake problem, thanks for that. I did my last wedding for this year yesterday so I am about to give the brakes a major overhaul...yes I still have problems! My main reason for the delay in fixing them is time. Renewing the brake shoes was quite straight forward. Removing the brake servo and possibly unearthing further problems with no time to fix was a concern (hence my enquiry to you Laurie the previous year). I had made a quick fix which made the brakes work quite well (don't ask, I can't stand the flaming!!!) I now have the time to remove the gearbox and servo etc to investigate the problem. Will keep you informed but I am sure it is just oil getting in the brake servo. I am servicing the master cylinder, both front brake expanders and renewing the flexi hoses, also the gearbox oil seal and brake servo lining are to be replaced. Will keep you informed on the progress. I have just revisited Ashley's site www.kda132.com and noticed it has grown since my last visit. I love the technical section, will be viewing the brake topic with interest, well done Ashley. Cheers Mark Anson
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Mark Anson
Experienced User Username: mark_anson
Post Number: 12 Registered: 11-2006
| Posted on Tuesday, 06 January, 2009 - 10:18: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
Hi All, Long time no speak! Just found this forum again after loosing all my favorites in a computer failure. Thought I would comment on this problem I posted a long time ago and end the story. It turned out oil was leaking onto the brake servo from a worn gearbox oil seal. Although the leavers and rods appeared to be working they only applied slight pressure to the brake shoes causing the braking effort to be low. I renewed the seal, plus the servo friction ring and my brakes work VERY VERY WELL! Thank you to everyone with there patience in trying to help me with my problem. I can look back now and appreciate I had no idea how this system worked hence the reason I made mistakes fixing the faults in the first place. Cheers Mark |
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Paul Yorke
Prolific User Username: paul_yorke
Post Number: 265 Registered: 6-2006
| Posted on Tuesday, 06 January, 2009 - 15:07: | ![Edit Post](http://au.rrforums.net/forum/icons/tree_s.gif) ![Delete Post](http://au.rrforums.net/forum/icons/delmsg.gif) ![View Post/Check IP](http://au.rrforums.net/forum/icons/checkip.gif) |
That's great to hear. I bet everybody's glad you didn't take the second option you were first offered! LOL. |
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