partly working brakes.........

Hi,
I have a 1999 TD5 manual. A few weeks ago i was coming out of a multi storey car park when the brakes almost failed. I say almost because i had to press really hard to make them work and then it was only the front passenger side that was working. I have driven some short distances on private land to see what was going on and it is still the same. What i have noticed is that the rear passenger side disc is completely rusty and the other two, front and rear drivers side, are slightly rusty. I have bled the brakes and believe there is no air in the system. By the way, the clutch works fine. What i have noticed though is that the fluid is leaking out somewhere. Not that i can see it on the ground, its just dissappearing from the resevoir. I can see no leaks in the engine bay either.........................any ideas?????????????????????
Regards, Colin

If you can't see brake fluid around any of the calipers or the master cylinder then may be its leaking in to the servo.

It sounds like your brakes fell back to a single circuit - they are split diagonally.

So, if NSF (near side front) is working, OSR would be as well.

Therefore NSR and OSF are the two that ARENT working, so the leak is somewhere on that side of the circuit I would guess. What I'd do is top up the reservoir, get somebody to pump the pedal and check from the master cylinder (it could be leaking at that point) all the way along those green steel pipes (which rust) through to the ABS modulator (check the connections on that - they can seep) then check the pipes to the OSF caliper. Check the two rubber flexi hoses inside the NSF wheelarch as both rear brake lines are there. Check the rear brake lines along the top of the chassis rail as best as you can see to the NSR caliper. The old steel brake lines are prone to rusting and can seep.

Good luck, and please post back what you found!

David

I'm confused, based on a D1 with ABS the two brake circuits are no split diagonally the primary circuit operates the rear brakes the secondary circuit operates the front brakes.

Even early models without ABS the primary circuit operates opposing pistions in each front caliper with the secondary circuit operating the other set of pistons and both the rear calipers.

Have things changed for the D2?

It the disc is rusty then that suggests that the piston is stuck in the caliper.

You made me go and double check it then ;-)

Just cross referenced both the D1 and D2 rave manuals:

D1 - as you say, two circuits, front and rear
D2 - 2 circuits, diagonally split.

David

My previous Disco (TD1300) had rusty rear disks, they were shot and the calipers had seized which was why they'd gone rusty I guess! Dunno much about brakes so I had the disks and pads replaced and the calipers freed off at a place in Surrey that I've forgotten the name of - very reasonable though I thought. About 200 quid all in and they could have charged me for new or recon calipers which is what I had been expecting but they just freed my existing ones off.

Sounds like seized callipers apart from the leak. An overhaul of the callipers would be a start to get the pistons moving followed by leak checks as previously discussed.

David Pye said:

You made me go and double check it then ;-)

Just cross referenced both the D1 and D2 rave manuals:

D1 - as you say, two circuits, front and rear
D2 - 2 circuits, diagonally split.

David

Click to expand...

Thanks for your time David, thats something i have learnt

discool said:

Thanks for your time David, thats something i have learnt

Click to expand...

We both did - I know my assumption about D1 brakes is wrong too

David

If you got a leak I'd get one of those EZ bleed kits. Connects yer spare tyre to the brake fluid reservoir and the pressure soon let's you know where any are..

Hi,
Thanks for all responses. Just to clarify a couple of points, i have checked all the linesunder the car and under the bonnet and can find no leaks at all. I have jacked the car up and all the wheels move freely so to me i would assume that the calipers are not seized. As mentioned before they were all working fine and then just suddenly went, it wasn't a gradual deteroation in performance. I have been out this morning and some of the fluid has disapperared out of the resevoir but there is no trace of it underneath on the car or the dry driveway. As you have noted it does seem to be that the front passenger and the rear drivers side are in much better condiditon than the opposing two.
Thanks for all your comments and keep them coming.
Kind Regards, TFP

Just a thought, is there fluid soaking into the carpet on the drivers side? That would suggest the seals have failed to the master cylinder.

The Flying Penguin said:

Hi,
Thanks for all responses. Just to clarify a couple of points, i have checked all the linesunder the car and under the bonnet and can find no leaks at all. I have jacked the car up and all the wheels move freely so to me i would assume that the calipers are not seized. As mentioned before they were all working fine and then just suddenly went, it wasn't a gradual deteroation in performance. I have been out this morning and some of the fluid has disapperared out of the resevoir but there is no trace of it underneath on the car or the dry driveway. As you have noted it does seem to be that the front passenger and the rear drivers side are in much better condiditon than the opposing two.
Thanks for all your comments and keep them coming.
Kind Regards, TFP

Click to expand...

The piston can seize in as well as out, also if a rear seal goes in the master cylinder the servo then can fill up with fluid therefore no trace of it. So unbolt the master cylinder and any pipe clips and pull it aside and look inside the servo.

Hi,
Thanks for all your replies. I have found the problem. It was a tiny little hole in the brake line. It was just above the rear wheel and sitting on top of the chassis.
Thanks again.