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Post by barryr on May 13, 2015 21:54:20 GMT
Hi all,
Discussed before but just looking for guidance. I noted the brake caliper I rebuilt last year had dust seals that had popped off the caliper body.
Those in the know will already realise the small brass retaining rings had dislodged. These were very thin and slightly damaged. In fact on the opposite caliper I superglued the dust seals in and gave up after the rings deformed on fitting but this time I'm looking to do the job properly and JRW now stocks replacement rings so I bought some.
The new rings are great. They are stronger and deeper than my originals. I've also split the caliper this time for easier fitting and already have the dust seal fitted and firmly retained.
The question I have is how to fit the piston through the dust seal. On the other side I got my son to push it in while I spread the seal with 4 fingers but is there an easier way?
These are the toughest calipers I've ever come across in terms of seal fitting!
Advice gratefully received as always...
Barry
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Post by Warwick on May 14, 2015 6:27:22 GMT
... JRW now stocks replacement rings so I bought some. The new rings are great. They are stronger and deeper than my originals... That's interesting news, Barry. Mine are probably like everyone else's; bent and lacking in springiness. I was lucky to find a set of NOS retaining rings on eBay last year, and they are sitting in my spare parts collection. But if an improved version is available; that's great news.
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Post by enigmas on May 14, 2015 7:53:20 GMT
Barry just wondering, when you split the caliper you also fitted a 'new' seal between the 2 halves?
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Post by johnwp5bcoupe on May 14, 2015 8:31:21 GMT
I am sure he will do Vince the GALLERY/BRIDGE seals are available, they used to come with the kit if not a bit of Googling and phoning! certainly not worth the risk using the old ones Best endeavours Barry I would think the professionals would have a tool to expand the boot so I guess it's loads of fingers again!
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Post by barryr on May 14, 2015 21:52:45 GMT
Right - I was really lucky and persuaded our lady " what does" once a week to assist! I presented her with a kitchen table set up ready and 2 shiny Pistons. I just said " pick that up and drop it in here while I hold this open!"
Seriously, the new Wadhams rings are better - taller and thicker and I found I could initially start them with a jam pot lid then lightly tap round the ring to fully seat. I also found they gripped far better by not smothering them in rubber grease like last time.
I did use a new galley seal as per previous advice. Powertrack in Slough supply them in pairs per caliper but you only need 1 per side so I have 2 spare for next time. They are cheap.
All done. Splitting the caliper is the best way to rebuild I think.
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Post by djm16 on May 15, 2015 2:52:37 GMT
I know you have done it now, but others may be reading this later will want to know how.
Once the seal is secured with the brass ring, I inverted / extended it so that it can stretch as far as possble from the caliper half. I then worked the lip of the seal over the piston crown, well lubricated with castor grease. The piston can then be eased into place and the seal worked up into the piston groove at the same time (provided your pistons unlike mine have the correct groove).
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Post by barryr on May 16, 2015 0:30:00 GMT
That sounds a great method but I didn't find enough flex in the rubber dust seal for starting it as you describe.
If you can prep a helper then with the caliper half on a surface with seal and ring fitted facing upwards, one person can use 4 fingers ( 2 on each hand) to pull the seal gently up into a square shaped opening while the second person just puts the piston in. You can then locate it and push home.
On one side I did struggle a little to not snag the seal as the piston went in. I just used very low air pressure from my compressor to push it out a bit and go again. I also used a blunt tool to firmly push the seal into the groove that you mentioned.
Hope it helps.
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Post by Deleted on May 17, 2015 14:03:00 GMT
That sounds a great method but I didn't find enough flex in the rubber dust seal for starting it as you describe. If you can prep a helper then with the caliper half on a surface with seal and ring fitted facing upwards, one person can use 4 fingers ( 2 on each hand) to pull the seal gently up into a square shaped opening while the second person just puts the piston in. You can then locate it and push home. On one side I did struggle a little to not snag the seal as the piston went in. I just used very low air pressure from my compressor to push it out a bit and go again. I also used a blunt tool to firmly push the seal into the groove that you mentioned. Hope it helps. I can hardly believe 10 years have passed by since I rebuilt the calipers on my car. I didn't split them and had a couple of spare sets of brass OEM boot sealing rings.They used to be supplied as part of the Girling rebuild kit. I remember one caliper took ages and the other about 10 minutes. I trashed a couple of rings in the process as they were so fragile.It's a knack but I've forgotten how I did it. It helps if you've got smallish hands and relatively long fingers (which I have) & also handy for playing the piano (which I do) When I rebuilt the front hubs and replaced the discs recently, I noticed that the seals were intact and sound. If I had to do it again, I might seriously consider the superglue method because the rubber boots are replaced on each rebuild anyway and I doubt whether new ones will last very long if other "new rubber" is anything to go by but it's always more satisfying to do the job "properly". It's good that JRW is remaking them and, if they're better and more robust than the original design, then £25/£30 (inc Vat & delivery) for four doesn't seem too bad.
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Post by lagain on May 19, 2015 19:56:52 GMT
I seem to remember that the last time I struggled a lot as I was trying to fit the dust seals with the piston nearly out.
I then pushed the piston in and it all seemed to come together. I did use super glue to keep the dust cover fitted in the piston
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