Posted From: 126.96.36.199
|Posted on Thursday, 15 May, 2003 - 12:33: |
I am in need of some advice. I have been overhauling the brakes on my S1 Bentley and am unable to get the to work properly. I have all new seals resleeved the master cylinders & wheel cylinders etc. The servo is fine & works fine. I know that the springs on the shake back stops need replacing as this is the only part that I have not had overhauled/replaced. I feel that at this stage I need to put my brakes in the hands of a specialist but the question is who? I would like advice on who to approach to work on my car, some who is fair, reputable wont cost the earth etc etc. I live just outside of Sydney. Any advice on this subject would be gratefully recieved. Thanks yours Craig D.
Posted From: 188.8.131.52
|Posted on Sunday, 18 May, 2003 - 11:44: |
What do you mean by not working properly?
No brakes? Very hard pedal? Pedal goes too far down before actuating brakes? Brakes pull to one side? Brakes are initially fine but then get hard to push on a long stop or descending a long hill? Sometimes brakes are very sensitive, but other times less sensitive? Too much servo lag? Brakes grab in reverse but very hard pedal in forward direction? These are just some of the symptoms that I would say are indicative of not working properly.
Please be specific with your symptoms, and we can help you figure out what is wrong.
Do you have the factory service instructions? Even though I have overhauled the brakes on many Clouds, I would not try it without the manual at hand. There is an adjustment of the master cylinder linkage that is done by measuring the position of the connection to the actuating linkage, which measurement I never seem to remember. I agree the servo is not a likely place for there to be trouble. Servos generally do not have problems.
I also do not think your trouble is with the shake back stops. You can check the function of the shake back stops by spreading the shoes and extending their return springs slightly, and see if they stay where they were extended. Then pushing inward on the front and rear shoe simultaneously you should be able to push them back in, but this should take a significant effort. I also do not think the shake back stop springs should ever need replacement.
Cloud brakes are very different from the brakes on any other car. Do not let someone who is unfamiliar with Cloud brakes work on them, even if he is very experienced with brakes on other cars.
Yet to post message
Post Number: 9
|Posted on Sunday, 18 May, 2003 - 13:20: |
Well my experience is different Bill. Apart from leaking master and wheel cylinders and worn drums my main problems have been with the servo. The things invariably fill up with oil and drop their efficiency by about 50%. The quick clue is to look for a drop of oil on the outer casing,if you have one there is a problem. It is not difficult to solve. Take the thing off having ordered a new lining and rivets and pull out the servo shaft with the seal housing. It is highly likely the shaft is scored from the crap that gets behind the servo and there is no seal made that will hold on this terrain. The cure is to fit a stainless steel Redi-seal sleeve over the shaft. These are available from bearing and seal shops. Then replace the outer seal with a double lip seal. The outer lip keeps the crap out and the inner one the oil in. Spring the Belleville washer on the back of the servo and make sure the mounting spring plates that hold the lining are not broken. They can be replaced. Fit the new lining, sand it smooth with fine paper, grease up all the ramps etc - check for brinelling, consider new balls (for the servo ramps)fit new felt seals, refit adjust all the linkages to specs in the book and fit seat belts when you test the brakes!
Posted From: 184.108.40.206
|Posted on Sunday, 18 May, 2003 - 21:21: |
Hi guys thanks for your input. Its hard to be clear we cant seem to figure it out at all . We are working from a workshop manual & have followed it accordingly. What happens is. you need to push very hard on the pedal & there is a lag or the front shoes do not seem to be pushing hard enough against the drums.It does not seem to be the servo as we have raised the car of the ground put it in gear given it some throttle & applied the brakes. The servo seems to do its job, all of the rods/linkages that activate the brakes moove extremely quickly as it seems that they should.However there is a little auto trans fluid & oil on the servo. I feel that this is from the auto trans & also from the lubrication system. Prior to overhauling the brakes the car stopped very quickly indeed when the brakes were applied. I do not have no brakes at all but it does take quite some distance to stop.
WE have made numerous adjustments ot the master cyclinder & have the right measurement. The rear brakes seem to be working fine. Is it possible that when applying the brakes when the car is actually moving there is some slipage in the servo? I can't figure it. Thanks again Yours Craig D.
Yet to post message
Post Number: 11
|Posted on Sunday, 18 May, 2003 - 23:52: |
See my post. (It is almost certainly a servo problem !!!
Posted From: 220.127.116.11
|Posted on Monday, 19 May, 2003 - 02:10: |
Well, it's not very hard to take it the servo out and apart to inspect for oil on the lining. (At least it is not as hard as getting the master cylinders out.) If you find oil, the source of the oil must be stopped. There is a seal, but also a drain to allow oil to escape that has passed the seal. All must be in good condition. Also, avoid excessive grease on the servo bearings. Then with a new lining, the servo should last "forever." I stand by my comment, the servo is not often a problem because the lining never wears out and the adjustment lasts almost as long. However, as Bill C says you must keep the oil from comming in to it. When servos are continually oily, the root problem is not being corrected. Oily servo is not a chronic problem that cannot be permanently fixed. You can stop the oily servo problem with a proper gearbox seal, an open drain, and the rest of the servo being sealed from oil ingress from the oilyness blowing back to it from up front.
Oh by the way, don't think of trying to clean off the oil from the servo lining. You might get it clean enough to allow it to work with some effectiveness, but the friction coefieient will be irratic resulting in a varying degree of brake sensitivity. Also it will be noisy, creaking and groaning as you pull to a stop.
Use caution riviting a new lining to the backing plate. Too heavy a hand with the hammer and punch against the new rivits will surely crack your new lining.
When reinstalling the servo, it is tricky to get everything properly aligned and seated. Make sure it is right before you tighten everything up. Also make sure the funny-looking pin retainer clip in the pull rod with the flexible end is on correctly. This clip prevents the rod from dropping down, flexing the wrong way, and ultimately being bent. Bent rods should not be straightened and re-used, and replacement rods are extremely pricy.
The pull rods are one of the very few places where BSF fasteners were still used.
Yet to post message
Post Number: 16
|Posted on Tuesday, 20 May, 2003 - 00:56: |
Generally I agree with Bill V. However I have cleaned out an oily servo many times with as-new results. In the early days of owning my R-Type, I was a penniless student, so a servo lining was equated to scooners of beer with my mates: quite a lot of beer to miss out on. Until I devised improved sealing, I cleaned it out whenever the brakes became slightly weak. The trick was to wash it thoroughly in petroleum ether (use ULP thesedays), then put the lining flat on a sheet of 320 grade sandpaper placed on a flat surface. By rotating the servo plate under pressure you can remove the glazed surface without changing the geometry of the lining. Once I had finally cured the oil contamination problem, and by then having a job, I replaced the lining with a new one. Guess what ? It was no better than a cleaned lining, but also no worse as these cars have superb brakes. The oil sealing was so good that I proudly managed to wear the new servo lining out after many miles.