Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: rooneysfoot on August 14, 2008, 09:32:58 PM

Title: braking problem
Post by: rooneysfoot on August 14, 2008, 09:32:58 PM

hi its my old 97 grand cherry 2.5td again!!!

ive changed pads and discs on the front brakes today and i now have no brakes!!

steve and myself spent a couple of hours bleeding the system and there seems to be air in it and dont seem to wanna come out i do have some brakes but not a lot

can anyone help??

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Post by: Tank on August 14, 2008, 09:43:39 PM

I know with the Cj,i had to ask Bubba about bleeding the brakes as i couldnt get the system to purge of air,and there was a particular order to bleed the brakes.Even then it took a while.I also know that some vehicles need a pressure bleeder to effectively bleed the system as the traditional method of manually  pushing the pedal wont work.

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Post by: MOCAJ on August 14, 2008, 10:14:36 PM

Lee has changed a caliper and disconected the brake lines so he could push the pistons back for new pads and discs. While he was doing this the master cylinder emptied of fluid.

by the time i got there, air was in all 4 wheel cylinders and even after going round them all 7-8 times and bleeding using the pedal we coudnt get it out

the pedal is not too bad without the engine running but as soon as it is started then it goes softer, can it be air trapped in the master cylinder or the proportioning valve  

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Post by: Ric Jacques on August 15, 2008, 06:12:52 AM

If you have chand pads and discs it's usual to have very poor brakes until they are bedded into each other.

Golden rule is to change front ones one week and rear ones the next week with a few hundred miles in between.

My 2p worth...........

Actually I just read the whole post I take it Lee is Rooneysfoot??????  In which case you have crappy brakes from replacing both discs and pads and also air in there to make things worse  

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Post by: Bishops Finger on August 15, 2008, 12:44:07 PM

Id agree with Ric

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Post by: mrzj on August 15, 2008, 01:27:39 PM

I had the same problem with the ZJ brakes when id had them in pieces to replace the ABS.

First problem was I had the back callipers on the wrong side, and with the nipple been at the bottom they wouldn’t bleed properly. (dumb I know!)

Second problem is that the master cylinder leans back slightly meaning air gets stuck at the front I put the back on some big ramps so it made the master cylinder level then re bled it and it was all roses and apple pie!

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Post by: Rodb on August 15, 2008, 06:47:06 PM

This is an old trick that I know worked years ago but I do not know why.

Pump up with foot pedal and get pressure in the system and then block the pedal down with pressure in the system. Walk away and come back in the morning remove the block and you should find that the pedal is much firmer.
I have used this system after a complete brake overhaul and bleeding the system did not give the pedal I wanted.

I assure you that it does work and can be done tonight, even with half a bottle of red wine ( inside you not the master cylinder). No dirty hands or bruised knuckles.

Give it a try, nothing to lose.

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Post by: Dave69 on August 16, 2008, 10:36:20 AM

ive always follwed the system of bleed the caliper initially first then start with the wheel the furthes away from the master cylinder then proceed to the one the closest.

i use a one way bleed system from halfrauds better than shouting a a friend with a spanner on the bleed nipple