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Brake residual valve
beaver34 - 10/3/14 at 08:58 PM

Any one running one in there front brake line?

I seem to have an issue with pedal travel on the front brake system, bled with no air but the first stroke of the pedal push travel is further as the pads go back to the disk

Apparently a 2lb residual valve is used in disk brake applications to remedy this looking about on the web

I have twin cylinder with m16 vented calipers, anyone else had issues with this setup?

Brakes work fine just lack confidence as the pedal travels differs over time


rusty nuts - 10/3/14 at 09:48 PM

Are you sure it's the front brakes causing the problem? Do you have discs or drums on the rear,if drums my first thought would be badly adjusted rear brakes. If you have rubber brake hoses try clamping each hose one at a time and test the foot brake to see which wheels are causing the problem. If you have rear discs slacken off the handbrake cable then pump the brakes a few times to adjust the calipers. another thing to try is make sure the pads are free in the calipers and not sieized


beaver34 - 10/3/14 at 10:03 PM

I can see its the front m/c taking up the free play whe operating the brake from above

All the lines are braided from m/c to calipers, it's running cossie rear disks

My other though is brake lines, I run a split banjo on the m/c the n/s hose as go go up ad over the bulkhead before running to the front of the car, s I possible the hose setup could cause an airlock that I cannot remove by normal bleeding?


britishtrident - 11/3/14 at 07:31 AM

Sounds like a seized piston or jammed pad in one of the front callipers.
Even when brand new M16 and P16 callipers are very prone to this problem especially if a piston is pushed fully home to fit new pads.



[Edited on 11/3/14 by britishtrident]


beaver34 - 11/3/14 at 07:47 PM

quote:
Originally posted by britishtrident
Sounds like a seized piston or jammed pad in one of the front callipers.
Even when brand new M16 and P16 callipers are very prone to this problem especially if a piston is pushed fully home to fit new pads.



[Edited on 11/3/14 by britishtrident]


How's best to check for this?

Strip them down and check that they more freely?


britishtrident - 11/3/14 at 08:09 PM

Remove a pad from one of the front callipers, place a tyre lever between the disc and calliper and get an assistant to gently press the pedal.
The piston should move out with out undue pressure and return when levered back relatively easily, repeat for each piston in turn.

Another possibility is of course a micro leak from a union these often let air in on the return stroke while showing only a tiny trace of a wetness when examined very closely.


beaver34 - 11/3/14 at 08:55 PM

quote:
Originally posted by britishtrident
Remove a pad from one of the front callipers, place a tyre lever between the disc and calliper and get an assistant to gently press the pedal.
The piston should move out with out undue pressure and return when levered back relatively easily, repeat for each piston in turn.

Another possibility is of course a micro leak from a union these often let air in on the return stroke while showing only a tiny trace of a wetness when examined very closely.


Will check this weekend, also will see if I can get a seal kit for the m/c to rule that element out

It's. .625 girling unit I think, any ideas where the best place for these seals are?

Thanks for your help!