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single wheel brake binding
Hodor - 28/5/18 at 10:49 AM

Here's a good one for you...

NSR brake is binding, quite pronounced, other rear wheel doesn't bind.

Suspected the caliper at first, so took it off and was a bitch to wind back, started to leak round piston as well, so I've replaced it with a new caliper.

Still binding NSR only.

Hmmm. From my master cylinder there is a single copper brake line going all the way to the back, which T's at the fuel tank to the left and right hub. So I break into the T and with the relief in pressure, the caliper frees.

OK, research tells me flexi hoses can swell, degrade inside and prevent fluid flowing back the way, acting as a one way valve and hence the release of the caliper. So I swap the left and right rear flexi round, NSR is still binding & OSR is ok = confirmation that its not the flexi.

So next I try relieving the pressure at the master cylinder by cracking off the connector pipe there. Caliper frees.

So why does the NSR bind, but the OSR not? Think I might have 2 problems - a dicky master cylinder not releasing pressure to the rear coupled with a crap OSR caliper (the hand brake doesn't work on this OSR caliper either). Seems unlikely?

Can anyone shed some light on the subject, or suggest some trouble-shooting?

Cheers.

froggy - 28/5/18 at 03:39 PM

Slacken the nuts holding the m/c to pedal box , if the bind goes it’s not returning fully

Hodor - 31/5/18 at 11:45 PM

quote:
Originally posted by froggy
Slacken the nuts holding the m/c to pedal box , if the bind goes it’s not returning fully


Genius! Went to look round servo and pedal, found a button head bolt wedged under the pedal so it couldn't return all the way home! Took it out and no binding caliper! Love it when the fix is that easy.

What has thrown me is that my osr caliper that I replaced was actually working fine, it's the nsr that wasn't binding that is shagged. Still, at least I know.

Thanks for the help!

froggy - 1/6/18 at 07:08 PM

A few years back a mate rolled his track car and a bunch of us helped re shell it over a weekend . Whoever did the brakes forgot to add the 1.6mm shim between the mc and servo which was the remains of a cut down bracket that supported the abs pump . Took some figuring out after the brakes started glowing after a few miles