Unable to bleed rear brake.

F

Fraserp6

Member
Over the last few weeks progress on my car has not been productive. One of the several jobs that does not seem to be going to plan it bleeding the brakes. Now, the Front brakes bled fine, however, when I attempt to bleed the rear brake nothing seem to come out of the rear bleed nipple when the pedal is pumped.

Prior to being bled, the car had fine brakes as far as I was aware, I just bled the system and the car hadn't been used in a few months, also it had been parked in the garage on the handbrake.

Anyone able to shed some light on this? In the meantime I'm going to comfort eat crisps.
 
Hi, i had a similar problem with my rear brakes last year. Firstly the N/s rear brake had a habit of sticking on, and then it got to the stage where the N/s/r brake wouldn,t work and nothing would come out of the bleed nipple.
After much head scratching i removed the rear flexi brake hoses (the chassis to O/s caliper AND the hose which joins both calipers. To my amazement, the hose which joined both the rear calipers was blocked. I couldn't even blow 120psi of air through it.
I replaced both hoses & the difference was amazing. The pedal feels positive & the brake response is improved. Therefore i would check your hoses first!!
I hope i have been of some help. :twisted:
 
Seconded Devilsplaymate. Replace those flexy hoses and all will be fine I suspect.

Working on the brakes is made much easier by taking the discs off too.
 
Hello from Germany,

on my recently bought P6 i have a similar problem bleeding the rear brakes. Front brakes bled fine, but nothing comes out of the rear bleeding nipple. We even unscrewed the hole bleeding nipple and applied full brake pressure to no avail. The funny thing is that the brakes work perfectly - no sticking, no unusual behaviour.
How can i remove the blockage there? I am thinking about poking in there with a small steel needle. Any other ideas? Since everything on that car is original (only 55.000 Km on the tach..) and the brakes/brake pads are fine i don´t want to pull the whole brake apart.
I appreciate any suggestions..

CU Olaf
 
I'd say it would be best to take the discs and calipers off and then replace the two flexi hoses and possibly the bleed screw too.

There's no sense in taking short cuts or trying to do quick fixes when it comes to brakes.
 
If the rear brakes work perfectly, then the hoses can't be faulty, otherwise one or both rear calipers wouldn't be operating.
I doubt that both calipers are working though, and would think there is indeed a faulty hose. I can't see there being a blockage between the piston on the N/S caliper, and the bleed nipple, although there's always a first time.
 
Could oport's car be German spec and have a dual circuit system ? That would give more possibilities for the problem but I agree that if the back brakes work on the foot pedal , fluid must be getting through
Did some cars of that era have a load sensitive valve which cut the fluid supply if the back end was jacked up ?+
 
Just a thought. If we assume that both rear calipers are functioning correctly the only thing left is debris in the left caliper after the cylinder and before the nipple port. If the old hose is failing internally a piece of dead rubber could conceivably cause a blockage that would stop bleeding. If you can remove the bleed nipple completely and probe with wire to break it up then maybe that'll fix things.

Cheers

steven
 
right, so today I'm under the Rover, attempting to remove the driveshafts, after much leverage, removed the four bolts connecting the disk and driveshaft, how do I now pop the driveshaft out so that I can slide the disk out to get at my flexihoses, which on first glace, look nackered.
 
You won't get the driveshafts to move outwards unless the wheels are off the ground and the weight of the car is supported on the body somewhere.
 
If you undo the pivot pin, which, apart from the handbrake linkage, is all that holds the calipers to the diff, then you'll have to remove the calipers completely, bcause once they are floating about then you won't be able to hold them to undo the pipes. So if you want to remove them, it's a 15/16"AF OE spanner for one end of the pivot and a 9/16"AF combination for the other, and sidecutters for the h/b clevises, and a 1/2"AF socket for the h/b bracket.

I never remove the calipers to do hoses, you can't justify the time to do it, I just do them on there.

You might find it easier to drop the rear end of the diff down to give you more room, but if you remove the 3 bolts holding it to the bearer plate they need Loctiting when you refit them.
 
Probably the most un-user friendly job I've ever done on any car. I principle, the rear brake system is quite clever, 40 years later, however, the system is a little stuborn.

Looking at the condition of my rear hoses, its a miracle I didn't die driving this car whn it was MOT'ed.

The rear hoses are clearly blocked with something, any idea what this is? does it suggest that something else is on the way out in the braking system?
 
Hello,

from the previous posts i assume that it is a good idea to change the hoses to make sure that there is no rubber etc. blocking the brake pipes. One question regarding that change:
Should I change the pads while doing that (they seem to be in good condition) and what do i have to dismantle for changing hoses and the pads? Everything else (discs etc.) is fine. I have that little special tool for the brakes (looks like a can opener) and a service lift is available, so no problem in getting under the car. Any recommendations how to achieve the job without tearing everything apart?

CU Olaf
 
If you only need to change the hoses , jack the car up , support the diff and undo 3 bolts holding it to the support crossmember
Lower the diff far enough to access your hoses and there you are
 
I've always worked on the rear brakes in-situ, but lowering the diff would be great for access. Soon I'll learn to use goggles, but I found that getting tools up in there to undo/tighten the bridging hose to the LH caliper and bracket is the only really awkward part. Next time I'm reconnecting the calipers immediately *before* fitting the pivot pins.

Taking the pads off for inspection can be a good idea. If they're very uneven, I think this will tell you if there's a problem with the self-adjusting ratchet and whether a seals job is in order. The outer pad is free as soon as you undo the two outward (towards the wheel) facing bolts on the caliper body. With the driveshaft out of the way the disc comes free and you can easily undo one of the bolts fixing the inner brake pad guide to the caliper body (and which also holds what I think is an anti-squeal tension spring), slide that little flat bar out and you can pull the inner pad. Removing the disc helps you get at everything without smudging the friction surfaces with dirt, fluid and other greasy stuff.

Winding the piston is pretty easy also without a tool (with pads out), unless the piston is close to seizing. If good, it can be done with your fingers.
 
Hi Dave,

I've done the brakes both with the diff in situ and with the diff dropped. IMHO it's worth dropping the diff, you can get at the hoses easiely, bleeding is much better because you don't have the carrier plate in the way and you can see what your doing with changing the pads. I've never pulled the half shafts on mine so maybe leave those and see how you get on.

For the pads; I followed the Rover workshop manual for mine and it wasn't horrible. Just remove the two bolts holding the bar that the pads ride on, pull the pads, wind the piston (I see you have the tool, it does help if you havent removed the discs) and slot in the new pads. One thing I did when I dropped my diff was undo the hose from the body to the right caliper. That way if the diff gets away from you you don't rip anything apart.

Have fun, it's not as bad as you expect working under there!

Steven
 
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