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+--- Thread: Hub seals and brake linings (/showthread.php?tid=1581)
Hub seals and brake linings - Tom Coates - 14-08-2018
I noticed that my back brakes were getting progressively more feeble and this is what I found:
On one side the linings had fallen completely to pieces and on the other side they were completely soaked in axle oil which had the positive effect of reducing the level of disintegration, but didn't do much for the braking.
Last year I relined the brakes and removed the hubs, filed off the high spots and replaced them with loctite flange seaer but no paper gaskets. Since then I have done Wiscombe twice, Prescott and about 500 road miles.
I see that there has been some discussion about keeping the oil/grease out of the brakes. The oil appears to be getting through the flange and not through the felt seal. I plan to fit sealed wheel bearings, reinstate the flange gaskets with a smear of hermatite or similar and drill some holes in the bottom of the axle tubes. What is the view of this approach?
Regarding the brake linings, these were the soft grey type and they appear to have split across the rivet heads. Possibly I clamped the rivets up too tight when I was fitting them and damaged the linings? I have another set which are made of a brown fibre with metal reinforcement and I suspect they may be a bit tougher? Has anyone come across this problem before? Is it worth getting bonded linings?
RE: Hub seals and brake linings - Steve Jones - 14-08-2018
Rather than looking to stop the axle oil getting onto the brake shoes, the better plan is to stop it getting into the axle tubes in the first place. What do you use as seals at the diff end of the tubes, traditional felts/cups or lip seals?
As to brake linings, the problem with bonding if using aluminium shoes is that the shoe castings can be be slightly porous. This means that over a period of time moisture can affect the bond between the shoe and the lining. In addition, oxidisation on the face of the shoe is difficult to fully eliminate meaning that the bond can be poor from the start. Bonding together with riveting is the best way to go and whilst I have done riveting myself, it works far better if carried out professionally. I've just had a set of shoes done with 'Green Gripper' at Saftec and it wasn't expensive.
Steve
RE: Hub seals and brake linings - Matt_Harnden - 14-08-2018
I have found the best solution to the issue of oil getting from the diff to the brakes is to reduce the amount of oil in the diff. This is a well known fix by A7 owners.
RE: Hub seals and brake linings - Tom Coates - 14-08-2018
(14-08-2018, 10:47 AM)Steve Jones Wrote: Rather than looking to stop the axle oil getting onto the brake shoes, the better plan is to stop it getting into the axle tubes in the first place. What do you use as seals at the diff end of the tubes, traditional felts/cups or lip seals?
As to brake linings, the problem with bonding if using aluminium shoes is that the shoe castings can be be slightly porous. This means that over a period of time moisture can affect the bond between the shoe and the lining. In addition, oxidisation on the face of the shoe is difficult to fully eliminate meaning that the bond can be poor from the start. Bonding together with riveting is the best way to go and whilst I have done riveting myself, it works far better if carried out professionally. I've just had a set of shoes done with 'Green Gripper' at Saftec and it wasn't expensive.
Steve
Steve,
There are no lip seals at the diff end, i know that would be the best approach but not keen to pull the axle apart!...
I'll look into bonding the linings, but obviously need to the get the oil issue sorted first.
tom
RE: Hub seals and brake linings - Steve Jones - 14-08-2018
Have you looked at this at about 2 mins 40 secs Tom?
https://www.youtube.com/watch?v=wkvjXnuiceA
Rear brakes seem to be working OK despite the oil!
Steve
RE: Hub seals and brake linings - Tom Coates - 14-08-2018
(14-08-2018, 02:16 PM)Steve Jones Wrote: Have you looked at this at about 2 mins 40 secs Tom?
https://www.youtube.com/watch?v=wkvjXnuiceA
Rear brakes seem to be working OK despite the oil!
Steve
yes its amazing really, maybe that's why the linings fell to bits! I was pushing so far I thought the pedal would go through the floor though.
RE: Hub seals and brake linings - Jeff Taylor - 14-08-2018
(14-08-2018, 10:47 AM)Steve Jones Wrote: Rather than looking to stop the axle oil getting onto the brake shoes, the better plan is to stop it getting into the axle tubes in the first place. What do you use as seals at the diff end of the tubes, traditional felts/cups or lip seals?
As to brake linings, the problem with bonding if using aluminium shoes is that the shoe castings can be be slightly porous. This means that over a period of time moisture can affect the bond between the shoe and the lining. In addition, oxidisation on the face of the shoe is difficult to fully eliminate meaning that the bond can be poor from the start. Bonding together with riveting is the best way to go and whilst I have done riveting myself, it works far better if carried out professionally. I've just had a set of shoes done with 'Green Gripper' at Saftec and it wasn't expensive.
Steve
Steve,
Having looked at Saftec's website, I can't see any mention of the 'Green Gripper' lining material you mention - what properties / advantages does it have over their standard and premium duty linings ?
Jeff.
RE: Hub seals and brake linings - Steve Jones - 14-08-2018
'Green Gripper' is their premium, woven lining. Called 'Green Gripper' because.......it's green!!
If you look at the picture at the top of the classic vehicle page on their web site you can see shoes lined with GG; they're the riveted ones. Put 'Green Gripper' into Google and you'll find out more.
Steve