Discussion
If its not the servo, then bleed all your brakes through with new fluid. If that don't do it then it could be the seals on the master cylinder about to give way.
check the valve on the servo first though. It should be a one way valve. Suck it and see?
Check all your slaves and all other conections and if it is the master cylinder buy a new one! brakes are important on a fast car so don't mess with the master with new seals!
good luck.
gadgit.
check the valve on the servo first though. It should be a one way valve. Suck it and see?
Check all your slaves and all other conections and if it is the master cylinder buy a new one! brakes are important on a fast car so don't mess with the master with new seals!
good luck.
gadgit.
I can only echo the comments made below...
1 - Check the Servo one way valve. This is push fit into the servo so make sure it seals well and only operates 'one way'.
2 - Check integrity of servo housing. Check the bottom has not rotted out as this will knacker the braking. It will also knacker the engine set up.
3 - DO NOT, I repeat DO NOT just replace seals in the Master Cylinder if knackered. Replace the whole thing for new.
4 - Check the rear brakes as these are often overlooked as they are drums. The shoes may be low or the cylinders maybe leaking.
5 - Once you are happy that all is as it should be and not leaking/knackered/corroded then check the pads are not glazed, breaking up etc etc.
6 - Check the condition of the disks. It may be worth having them regressed if they are looking shabby.
7 - Check the brake lines are not ballooning or leaking or have unusual kinks etc
8 - Bleed the brakes doing the furthest corner from the reservoir first. DO NOT bleed the system dry and then refill as the master cylinder will not like this. Nor will the bias valve.
9 - Replace DOT 4 fluid for DOT 5.1 if you are using them very hard.
10 - Even better replace the brake lines for braided ones...
11 - Put the kettle on and and sit back in the knowledge you've done the lot and sorted the problem.
Cheers
Mark
1 - Check the Servo one way valve. This is push fit into the servo so make sure it seals well and only operates 'one way'.
2 - Check integrity of servo housing. Check the bottom has not rotted out as this will knacker the braking. It will also knacker the engine set up.
3 - DO NOT, I repeat DO NOT just replace seals in the Master Cylinder if knackered. Replace the whole thing for new.
4 - Check the rear brakes as these are often overlooked as they are drums. The shoes may be low or the cylinders maybe leaking.
5 - Once you are happy that all is as it should be and not leaking/knackered/corroded then check the pads are not glazed, breaking up etc etc.
6 - Check the condition of the disks. It may be worth having them regressed if they are looking shabby.
7 - Check the brake lines are not ballooning or leaking or have unusual kinks etc
8 - Bleed the brakes doing the furthest corner from the reservoir first. DO NOT bleed the system dry and then refill as the master cylinder will not like this. Nor will the bias valve.
9 - Replace DOT 4 fluid for DOT 5.1 if you are using them very hard.
10 - Even better replace the brake lines for braided ones...
11 - Put the kettle on and and sit back in the knowledge you've done the lot and sorted the problem.
Cheers
Mark
If your start the car and then go to the engien bay you will be able to see whether the vacuum is collaping the pipe simply by looking at it.
Do not disregard the possibility that the pipe is blocked.
My process would be this....
1 - start car and rev it lighlty to gaurantee there has been vacumm created.
2 - stop engine
3 - remove the the one way valve out of the servo. There should be an audible 'hiss' as the air is let in between the valve and the seal. This will prove the integrity of the servo and the 'one way' property of the valve.
4 - to double check the valve and pipe. Remove them both from the servo and 'suck it' and see.
5 - Refit all the parts if no falt found and then restart the engine
6 - Get someone to depress the pedal whilst you watch and feel the pipe for collapse.
BEWARE - This is a point I have shown many people with S's and one I shall detail for you hear while you've got you're head in the engine bay......check that the rear brake line from the bias valve running along the bulkhead on the drivers side is not rubbing against the clutch master cylinder brake line which is in the same area. I have seen this happen so badly that the rear brake line failed and caused a pin prick hole. Enough for the rear system to be redundant and the line to spray a fine mist of highly flammable brake fluid all over your nice hot exhaust manifold !!! It is easy to bend them away from each other and if you're really bothered then you can get 'thingy' that hold pipes apart. An inch clearance should be fine though..
Cheers
Mark
Do not disregard the possibility that the pipe is blocked.
My process would be this....
1 - start car and rev it lighlty to gaurantee there has been vacumm created.
2 - stop engine
3 - remove the the one way valve out of the servo. There should be an audible 'hiss' as the air is let in between the valve and the seal. This will prove the integrity of the servo and the 'one way' property of the valve.
4 - to double check the valve and pipe. Remove them both from the servo and 'suck it' and see.
5 - Refit all the parts if no falt found and then restart the engine
6 - Get someone to depress the pedal whilst you watch and feel the pipe for collapse.
BEWARE - This is a point I have shown many people with S's and one I shall detail for you hear while you've got you're head in the engine bay......check that the rear brake line from the bias valve running along the bulkhead on the drivers side is not rubbing against the clutch master cylinder brake line which is in the same area. I have seen this happen so badly that the rear brake line failed and caused a pin prick hole. Enough for the rear system to be redundant and the line to spray a fine mist of highly flammable brake fluid all over your nice hot exhaust manifold !!! It is easy to bend them away from each other and if you're really bothered then you can get 'thingy' that hold pipes apart. An inch clearance should be fine though..
Cheers
Mark
Christ Johno! he's only got bad brakes not a complete rebuild! would you like to see me hard top on the S. Now there's a thing! You see I bought this hard top off a bloke in Oxford (bit of a down and out) but I took pity on him as he was unemployable. Its not on properly yet but it looks great (I think) Funny thing is I even bought a set of springs off this bloke as well. I think he said something about fitting a cosworth engine in a mini?
gadgit.
>> Edited by gadgit on Tuesday 20th August 19:31
gadgit.
>> Edited by gadgit on Tuesday 20th August 19:31
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