| Author | Message | ||
     Mark Anson New User Username: mark_anson Post Number: 3 Registered: 11-2006 |
Hi All, If you remember I posted a message about the brakes and servo etc on my MkVI last year. In the last two weeks I have been stripping down my cars braking system and found a huge list of problems (most now sorted). 1. Brake servo full of oil. (now cleaned and relined) 2. Gearbox oil seal leaking (replaced) 3. Master cylinder seals worn, body full of dirt. (cleaned - seals replaced) 4. Master cylinder cap breather hole clogged. (cleaned) 5. Flexible brake hose walls collapsed/restricted. (renewed) 6. Front brake expanders full of dirty fluid/debris. (cleaned - seals replaced) 7. Bleed nipples seized solid/now snapped off! My problem is number seven! Even after leaving both expanders soaking for several days the bleed nipples (badly corroded and chewed up with mould grip teeth by previous owners) both snapped off whilst trying to remove them, even with heat. I have looked at the picture in the service manual at the cutaway drawing but the nipple is not shown. There is mention of the ball bearing that sits under the nipple, its this that has me worried. I need to know what shape the nipple is at the end when its removed. On modern wheelcylinders there is a tapered hole that the tapered pointed nipple screws into, I am not sure what the Bentley has. I am trying to drill the old nipples out and do not want to damage the expanders casting. Does anyone have a picture of a bleed nipple and would you know what thread size and pitch etc is used in tapping the hole? Are these nipple something that can be easily obtained here in the UK? Does anyone have a part number please? Thanking you all in advance Mark Anson | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 626 Registered: 9-2004 |
Mark do not drill at this stage. I have been waiting for others to come up with the old workshop way but alas it seems none to date! My method taught to me many years ago is ok on alloy and cast cylinders. Will do a set of pictures for you and others as the easy way forward on this problem, not in the manual. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 627 Registered: 9-2004 |
Mark, this practice can also be carried out on calipers with broken bleed nipples as well. I learnt and have always used a stick welder but this i carried out with the mig. This is for the enthusiast who is not in the position with an open cheque book and does not wish to go to a specialist but have a go himself. Broken manifold studs and head studs can be removed in a similar way without the removal of engines etc. Do not try this if your eyesight is not good close up,also if you suffer with the shakes!Get a good mig operator to do it for you. Picture 1 bleeder snapped off. 2 building up broken bleeder. 3 nut placed over and ready to weld. 4 nut just welded[hot] threads free to turn when cold, well almost. 5 bleeder on its way out. 6 ballbearing in its housing seat with the bleeder removed. Hope this helps. Any questions welcome.       | ||
| David Gore Moderator Username: david_gore Post Number: 672 Registered: 4-2003 |
Hi Pat, Thanks for all the trouble you went to with the photographs showing how to solve this difficult problem. Kind regards David | ||
| Mark Anson New User Username: mark_anson Post Number: 4 Registered: 11-2006 |
THANK YOU PATRICK!!!!! I removed both nipples like you described and they are now out. I had tried using a blow lamp and easy outs but this just made the hollow nipples spread. The direct heat to the nipple from the mig weld freed the little devils off. My only problem now is the replacement nipples! Flying spares have just sent me two (at £6.00 each!) but they are the modern type - with the pointed end. You can see from your exellent pictures the original ones have a flat base with a dimple in for the ball bearing. Do you know if the modern version will do the same job, especially if you remove the ball bearing? Thank you for all your trouble, especially the pictures. You are a lifesaver. Mark | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 628 Registered: 9-2004 |
Hi Mark, Regarding the original bleeders they are 5/16 BSF. The later type will not fit. Not a hard job to make some up if you cannot source any out of 5/16 BSF set bolt. Position a nut and weld for undoing for bleeding. Drill a dimple in the end for the ball bearing as this must be used on that type of w/cylinder seat. Drill for the fluid bleed the same as the original bleeder[through the side bottom to middle and then down the centre to bottom drilling]. If you were closer i would get some to you as we still have old stock. Main prob is the bleeders blocking,not the bearing sticking [it cant unless wrong size ball is fitted] when they are slackened off when no fluid comes out! Rubber caps are a must. | ||
| Mark Anson New User Username: mark_anson Post Number: 5 Registered: 11-2006 |
I spoke to Flying Spares today and they asured me the bleed nipples are a straight replacement for the old type (the thread is the same). I asked about the ball bearing and they said just remove it and leave it out. I am not fitting these nipples untill the weekend but was now a little unsure what to do for the best. I presume the nipples point will sit into the hole the ball bearing did as this is in the center. Any thoughts? Mark (Message edited by mark anson on November 30, 2006) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 629 Registered: 9-2004 |
Hum Mark,if yours are not 5/16 BSF but the larger type then yes the pointed type will fit without the ball. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 630 Registered: 9-2004 |
And the larger type fitted may be 3/8, 24 TPI. | ||
| James Senior Yet to post message Username: jamess Post Number: 1 Registered: 9-2016 |
Hello everyone! I'm briefly reviving this old topic as I feel I can close it satisfactorily. I've been trying to buy spare parts to rebuild two seized front wheel cylinders on a 1949 Silver Wraith. Like the original poster, I found that Flying Spares only supply modern style 5/16 BSF bleed nipples with the cone on the end. I have since discovered a supplier of Stainless Steel blunt ended bleed nipples which are practically identical to the originals, so thought I'd share! CCS fasteners: http://ccsfasteners.co.uk/blunt-stainless-steel-bleed-nipple-p-2019.html Hope this may be of use, James  | ||
| David Gore Moderator Username: david_gore Post Number: 2208 Registered: 4-2003 |
James, Thank you for this information - I am certain it will benefit owners of Early Post-WW2 vehicles. P.S. Did you get my response to your recent message through the RRBEW website? | ||
| Norman Geeson Unregistered guest Posted From: 81.97.26.213 |
For anyone thinking of replacing these front brake bleeder nipples they would be advised to read the www.KDA132.com web site, brake section on rebuilding late type brakes page 7.This gives all details of these bleeder nipples and part numbers. The problem with the automotive industry, I suppose like others is that memory fades or people commenting were not around at the time. I can tell you that circa 1963 Lockheed in particular issued a bulletin advising fleet users to replace ball retaining brake bleeders with the tapered type. Stating in essence that the tapered bleeders would form a new seating. Fleet engineers in the 60's faced the same problem some are facing today and these problems were solved at the time. (Message approved by david_gore) | ||
| christopher carnley Unregistered guest Posted From: 5.80.52.169 |
David, I think that RRBEW was dissolved some time ago due to the high incidence of troll-ery. (Message approved by david_gore) | ||
| David Gore Moderator Username: david_gore Post Number: 2211 Registered: 4-2003 |
Christopher, The RRBEW website is still accessible and there have been infrequent posts since John Prescott suspended his involvement. The content of the message was something that only James could have asked relating to our past contact. | ||
| James Senior New User Username: jamess Post Number: 2 Registered: 9-2016 |
Hi everyone, first things first, David, I have tried to reply to your mail on the other forum twice, but my replies don't appear in the email history, so something is awry! There's no need to send me a copy of the scans back as I have the originals, but please let me know when you manage to clean them up. Norman, thank you for sharing the link to what appears a technically invaluable website! I always appreciate opinions and guidance, especially when it's based on experience. Regarding the two types of bleed nipple, I can appreciate the positive aspects of the ball version, on paper at least, which the engineers may have originally had in mind: a ball bearing is a readily available, very hard and finely polished surface with which to form a seal; the bearing won't rotate against the seal as it's nipped up (as there's less friction at the point-contact to the bleed nipple) and finally the ball bearing can accommodate any inconcentricity between the hole it seals against and the thread. Of course this is probably complete overkill for something that's not exactly operated every day! I suspect the switch to the cone design later on was based on equivalent performance with fewer components, with the added bonus that there's no ball to slip out of position if you unscrew the bleed nipple too far! With both parts in my hand, I intend to try the blunt type first primarily because it's marine grade Stainless Steel. I also like that it's closer to the original, but that's not essential, so if for whatever reason it doesn't work I shan't hesitate to swap it out with the cone type. Finally, it does seem a little overboard to have two forums for what is presumably a relatively small community of enthusiasts! Are the most helpful contributors members of both - or should I post any future questions to both forums for maximum exposure?! All the best, James | ||
| David Gore Moderator Username: david_gore Post Number: 2223 Registered: 4-2003 |
"Finally, it does seem a little overboard to have two forums for what is presumably a relatively small community of enthusiasts! Are the most helpful contributors members of both - or should I post any future questions to both forums for maximum exposure?! James, I suggest posting in both forums as both have their individual as well as shared readers. The main difference is our forum covers the Shadow and later era models more extensively whereas the KDA132 website specialises in the early post-WW2 models. I have sent you a PM through the RRBEW site this morning. "Everything comes to those who wait!!!!!". | ||
| NORMAN GEESON Unregistered guest Posted From: 81.97.26.213 |
David The other points about these forums is that there is no public discussions on the KDA132 web site, quite deliberately. There are also sites that are viewed by some but those same people do not participate with answers. For example, I do not participate on the BDC site and very rarely on the RREC. Unfortunately some have a reputation for, let us say, inaccurate or misleading answers. I am not alone on this issue, and as you suggest posting on more than one forum is likely to throw up an answer. (Message approved by david_gore) |
