Right where do i start car has had abs taken off and all bits from a xr3i fitted problem is it failed its mot as there is play in peddle when engine not running,it should just go rock hard but it dont ive now changed every thing i can think off master cylinder,servo, both rear wheel cylinders ive bleed the brakes you get all air out then u try again an there is more in system there is 1 other thing when pushing peddle down u can hear air coming out of some where under bonnet so when checked there is air coming out of bottom of the brake servo where the master cylinder join,now i thought it was meant to be air tight but by the look of master cylinder its meant to leak air as it has an indent round the seal so air can get past???? weird is it meant to be air tight as i would have thought so if is its a bit shady way of making master cylinder.this is my last chance to sort if not better get wallet out as its going in to a garage to get sorted as ive had enough now

jon

 

dont think its ment to leak air! mine dont!

 

im an mot tester, & without refering to the testers manual feel, you can only fail a brake pedal for being insecure or hitting the floor (no reserve), ie anchor/pivot points worn/loose or no brake pressure. also the master cylinder has nothing to do with air, its purely fluid operated, the servo & air tube to inlet manifold is the only brake componants that can leak air, & when one fails, the pedal will feel hard to press down with poor stopping power. if there is no hissing from the servo/pipe, & the brake perfomances are ok (over 50% of the cars wieght) the brakes should pass, ask them to show why it fails in the manual (under reasons for rejection). if no joy, try taking it elsewhere, & if it passes there, report the incedent to vosa

 

thing is brakes just dont seem to have any pressure this i think is due to air coming out of servo to master cyl join.as everytime press peddle down it just go all way down now while you can here air coming out of join its deff got to be this but it just dont look right as where its coming from looks like its meant to let air out ????? right anoying as its prob some thing stupid

 

sound to me like the master cylinder seals have failed, except for brake fluid leaks or boiling, the master cylinder is the only thing to allow the pedal to travel so far, if the servo has gone (& not the master cylinder) the pedal should be hard to press & at the top, its possible the master clinder has leaked fluid into the servo & rotted the diaphram (but ive never come accross it) start with the cylinder. also if the servo is leaking that bad, you must have a really poor idle

 

well i went to scrap yard and got a new master cylinder and servo from a 1.8 diesel tried peddle and it went rock hard with no engine running took it off car with out taking apart.fitted it today an brakes still same but still go straight to floor there is still a bit of air in system still but cant see it would make it do it this bad ???? also there is same hisssing noise and air coming out from join in master cyl and servo.it did not do this on car i took it off??? any other ideas anyone as dont no what else to try

 

Servo's gone.

Colin.

 

cant be unless im very un lucky as its now had 3 diff ones which i no worked fine an still does it

 

your problem must be elsewhere then jon, if u can hear a leak, that must be your problem as u have tried everything else!, where the master cylinder meets the servo, int it meant to be air tight, think mines got all sealer around it,

also is that pipe from the inlet manifold nice and tight, other than that put the abs back on!, thats why i left mine on!, didnt want more problems!

 

Use the easy bleed system. It took ages for mine to clear. Did you take the bias valves off the back? I had the same problem and it turned out the valves on the back had siezed so I bypassed them and cut them off.

Cheers
Dave

 

There's no seal between the master cylinder and the servo.

Where's the sound of air coming from ?

I had the same prob on the S1 after I'd had it in bits for 4 years and it was the servo diaphram (spelling ? ) that had failed.

Colin.

 

the air is coming from join in master cyl to servo u can feel it coming out.. i bleed the brakes propperly with an easy bleed kit today and think i might have found the problem i got peddle to go quite hard but still not right. the rear drivers side when bleeding no fluid came out for ages then got it to come thew and if i keep pumping for ages it seem like nearlly all air is gone but when u stop try again loads and loads more air come out so sounded like got an air leak.i had a new piece of brake line made up the other week and one of the ends has not got right one think its concave or convex but its wrong one so looks like its not been sealing propperly going to get new one made tomorow so hope fully will be sorted

 

The easybleed system is really good. If you've got any leaks it will find out before you take it out on the road. Worked for me.

Cheers
Dave

 

Ezibleed was the only way I could get my brakes to bleed after I rebuilt my car.

Good luck.

Colin.

 

Any updates from this,is the problem fixed now??Regards Micky

 

yes now fixed changed both rear wheel cylinders both small brake pipes servo an master cylinder bleed brakes an there fine now