Citroen ZX (1992 - 1998) - 1995 1.9d Bleeding problems?

Honest John Back Room » Technical matters
View Threaded
Mon 12 May 2008 23:31
1995 1.9d Bleeding problems? - telecaster
I replaced the master cylinder on a citroen zx 1.9 diesel,also replaced rear wheel cylinders.

Handbrake was not holding so adjusted the pawl on both rear drums resulting in a nice firm handbrake.

My problem now is after bleeding whole system the brakes feel mushy with no stopping power......it feels like there is still air in the system!

I removed both front calipers(bendix) and pushed pistons in and out to check they were not siezed, I also greased the sliders/pins.

with the rear wheels raised the handbrake is holding firm yet pressing the brake pedal results in the wheels not holding firm???

I have read horror stories about citroen brakes.....have I bled them in the wrong sequence or have I missed something else?

Someone also mentioned a "dosseur" valve on some citroens....what exactly is this and has the zx got one?

I am really stumped on this one and would really appreciate some advice.

Ta in advance.
Reply | Report as offensive | Link
Tue 13 May 2008 09:14
1995 1.9d Bleeding problems? - RichardW
You have't got a Doseur valve - this is equivalent of a master cylinder on Citroens fitted with hydraulic suspension.

Did you fit a new master cylinder, or was it used - sure it was the right one?

I suspect you have not got all the air out of the rear brakes and / or the adjsuters are not set up right. I'd bleed the rear brakes again, preferably using a eazi-bleed or similar, and make sure you bleed plenty of fluid out to make sure the air is gone.
Reply | Report as offensive | Link
Wed 14 May 2008 18:16
1995 1.9d Bleeding problems? - telecaster
Thanks for the reply Richard.

The master cylinder is the same tho it is second hand.

I have set up the rear drum adjusters so the drum just clears the shoes......resulting in a nice firm handbrake.

Yet when I press the footbrake with rear wheels in the air the wheels still spin with very little resistance!

The wheel cylinders are new and the shoes have plenty of meat on them.

I have also run approx 1 litre of fluid through the system in an attempt to bleed it.

Any further advice appreciated before I burn the car!

Marty.
Reply | Report as offensive | Link
Wed 14 May 2008 18:36
1995 1.9d Bleeding problems? - 659FBE
With rear drum auto adjusters which let the pistons "follow" the shoes rather than taking up the slack between the piston and the shoe web as the lining wears, it's possible to end up with a trapped air bubble in the rear cylinders in the space between the two pistons.

I have no first-hand experience of the ZX but this has caught me out on other cars with a similar configuration. The fix is to remove the drum (hard luck) and use a G-cramp to hold the two pistons together in the fully retracted position. Then bleed that cylinder and do the other one. It's usually possible to do this without removing the shoes with a little ingenuity.

As far as the brakes being inoperative with the rear wheels in the air, does this car have a load sensitive valve? This will shut off the fluid to the rear cylinders under these conditions - it also affects bleeding too.

659.

Edited by 659FBE on 14/05/2008 at 18:37

Reply | Report as offensive | Link
Wed 14 May 2008 18:38
1995 1.9d Bleeding problems? - Number_Cruncher
>>use a G-cramp

I simply use a cable tie to hold the pistons together - strapped right round the wheel cylinder - while you're bleeding the brakes, it isn't as though there's any real pressure in the system. This neatly avoids having to take the shoes off.

Reply | Report as offensive | Link
Wed 14 May 2008 23:50
1995 1.9d Bleeding problems? - yorkiebar
You are going to have to do this again!

Release the handbrake and slacken the cable adjuster right off.

Then and only then set the auto adjusters for the footbrake until the pedal and action is firm. Re bleed it if needed at this stage. You will know whether it is bleeding issue or adjuster issue now!

Then, and only then adjust the hanbrake.

Adjusting the handbrake on these (and similar) models before setting the footbrake adjustment will ALWAYS result in a good handbrake but poor footbrake .

hth
Reply | Report as offensive | Link
Thu 15 May 2008 10:17
1995 1.9d Bleeding problems? - M.M
ZX brakes with the rear drums are very prone to poor performance and a stodgy feel. They can need going right through with all new parts to get them anywhere near.

A couple of comments on your problem.

Might be worth replacing the rear shoes, they may look OK and you'd think the adjusters would bring worn shoes close to the drum but it doesn't work like that.

Also the biggest thing... fitting a used master cylinder is a big no for me. I'd never ever fit used braking hydraulic parts. How do you know it isn't in poor condition?

David
Reply | Report as offensive | Link