Mot Failure (wifey's Tin-top)

[Snapperpaul]

I used Andys idea with the cylinder on my hood after i experienced the same problem you have. It drove me up the wall.

Take off all the pipes, fill with fluid, flush through with nothing in the holes, i used a lot of old fluid at this point as you are just flushing any air through, put in the 3 bleed nipples,flush through the single output now using new fluid until clear of air, nip up, same for lower nipple of the twin output section then on to the top one.

When complete test pedal for creep, this is the time you find out wether your new secondhand master cylinder is at fault.

If all O.K. then you have to try and attach the pipes without getting any air in, not easy but if your resovour is full and your quick then it can be done.

Now bleed the system from the furthest back.

 

NOTE. If you have flexi pipe clamps then clamp up your brake cyliders before undoing the master cylider. When you do the final bleed, bleed then clamp each one, then undo one at a time and test pedal for creep, if individualy O.K. undo the back two, test, then front two, test, this should isolate each system if its a front back dual system ( it may be a diagonal split system you will have to determine this). If all is O.K. at this juncture then unclamp the lot and pray to your respective God.

 

It eventually worked for me after using a lot of fluid.

[enforcer]

Day four.

 

Thanks for staying with me if you're reading this...

 

This morning I removed both pipes from the master cylinder and plugged with new bleed screws. Bled these out and hey presto - rock hard pedal with no movement even with the engine on. Guess this means my master cylinder is good.

 

Bled the whole system again - problem still there.

 

The system is diagonally split - rear offside and front nearside in one pipe, rear nearside and front offside in the other. Playing around with the clamps I have determined the following:

 

If I clamp both front flexies I have a good, firm pedal with no creeping.

 

If I clamp both rear flexies the old problem of the pedal creeping to the floor is still there.

 

From this is it safe to deduce that the problem lies with the front calipers? If this is the case (and bearing in mind I have already swapped the originals with a pair from the scrappies) this would have to mean that I was unlucky enough to buy a second faulty pair of calipers. All I can do now is replace the calipers with new ones for about £100 and try again....it's just that I've got a horrible feeling that the creeping will still be there!!!

[Longboarder]

Rich so far you have proved the new master cylinder and the rear parts of the two diagonaly split circuits. Earlier in the thread you said that clamping one of the front flexis gave a hard pedal effectively identifying a fault in the front part of one diagonal split, either balloning hose, air or a faulty caliper. You then, illogicaly IMO, went on to change both front calipers rather than concentrating on the side of the identified fault. And a fault is still present. It may not be the same fault!

 

Then you say that clamping both front flexis now cures it. This only rules out the rear parts of the two circuits and the master cylinder. You have to retest each side of the fronts. First check you have fitted the calipers on the correct sides, bleed nipples uppermost so you can get the air out of the system!

 

Clamp one front side flexi as close as possible to the solid pipe from the m/c and test pedal. Repeat, same side close to caliper, ie this time testing the flexi. Repeat both tests on other side. This should help narrow it down to flexi or caliper. Incidently if you get pedal creep and the resevoir level is not going down it's air in the system or ballooning hose.

 

Hidden fluid leak into servo can be hard to find but fluid level drops and smoke from exhaust are giveaways.

 

Nigel

[enforcer]

You then, illogicaly IMO, went on to change both front calipers rather than concentrating on the side of the identified fault

 

Guilty!

 

Good tip re clamping the flexies top then bottom. Amazingly although the rigid pipe ends at the top of the wheel arch, there are no fewer than 3 separate flexies joined together before the caliper!

 

I might go ahead with just one new caliper at first. If there is no difference then at least I can keep the cost down a little. But as you rightly point out, you've got to change one thing at a time!

[Guest john]

I fancy the knackered flexible theory myself. We could not get a hard pedal on the turbo,had the same creep that you describe, and traced it to the flexi's around the ABS unit. Once changed , it was fine.

[Guest vince]

I do hope not. Gonna sleep on it and tomorrow knock the master cylinder question on the head by trying Andy Parry's idea of blocking off the pipe exits with new bleed screws and isolating the master cylinder.

 

If doing this shows that the pedal is firm and no longer 'creeping' at least I won't be forking ou £125 + vat for a new one!

 

 

Have you tried a complete brake fluid change as it can deterate and have similar symptoms but the amount of work you have done it sounds as if you have put alot of new fluid through it.

Vince

[enforcer]

Vince, I'm up to 3 litres through the system now!

 

John / Nigel, I think we might be onto something here. I have found that crimping the flexies at different points effects how far the pedal will hold. I did think that there were several flexies joined together, but on closer inspection it is just one with several brackets swaged into it at the mounting points. Having freed the pipe it does feel quite soft and pliable in places, but hard and fixed in others. Gotta be worth replacing these whatever, but this might just be the problem. God I hope so. Mind you I can't imagine they are going to be cheap!

 

Good thing about being a kit car owner is that you always have plenty of shiny new nuts and bolts to replace the old corroded ones! The moisture on the pipes and brackets is WD40, not brake fluid!

 

[enforcer]

I give up.

 

Two new flexies fitted (£53) and bled again. Still the same damn spongey pedal. Even the copper sealing washers for the banjo joints had to come from Rover at £1.20 each!!!!

 

It's booked into the MOT garage for Wednesday morning. Tempted to replace the front calipers with recons but frankly I've had enough and I can guarantee that another £120 gone and the problem will still be there.

 

If this was the hood it could sit in the garage until I calmed down , even if that took a couple of weeks, but I need this car back on the road next week!

[Guest TerryBarry]

You seem to have replaced most items and still have same problem.

Just a thought - could it be a mechanical problem on the caliper / swivel hub mounting [cracked bolt hole or something]

[steve in stockport]

are you still bleeding the brakes manually?

 

sometimes you can get a bit of air trapped that no end of steady pumping can shift and will infuriate you for ever.

pressure bleeder wil usually move it along with the flow of fluid.

 

i've got one you can use if you can get to the staffs meet tomorrow night to collect it

 

Steve

[enforcer]

Thanks Steve, but I've got a Gunsons job - problem is the top of the Rover master cylinder is about 3" across - nothing in the Gunsons kit comes near.

 

I've seen a DIY job on Rovertech built using a glass jar and some tubing (acts as a vacuum and sucks the fluid out from the bleed screws using the engine manifold vacuum). But if truth be told I've lost interest now. I had booked a week's annual leave to have a bit of time with the family at Easter and have lost 5 days working on that car. Hence drawing a line under it and am now sat on my a*se enjoying a glass of wine. I might have a tinker over the next day or so if something springs to mind, otherwise someone else can struggle with it.

[enforcer]

Finally all sorted. Garage re-bled the entire system, bleeding the ABS high pressure system as well. They retracted each piston and bled through with a pressurised system. Apparently there was still some air in the rear callipers.

 

Another £75 worth of labour and brake fluid, but the brakes are amazing now!

 

Thanks to everyone who helped out with this. As a reward for all my hard work I was allowed to go and get my Road Tax, and had an awesome drive out in the Spring sunshine. (Still picking the bugs out of my teeth)!

[Guest john]

Nice one, glad its done now ?

 

weather looks pretty good for a few days yet , time to enjoy your hood driving now.

[enforcer]

Too right John! Clocked up a few miles yesterday. Kids are staying with their Grandparents in Devon at the moment, so I actually persuaded Mrs Enforcer to come out for a drive - first time ever .

 

This was a mistake.

 

Having spent over two years resenting every penny and hour I have spent on the car she has now realised what the fuss was all about. Numbed from her enthusiasm I even agreed to let her have a drive. I'm afraid she enjoyed that too. I phoned my son (who up to now has been my only '2B Buddy'). He was gutted!

[Guest paulh]

Too right John! Clocked up a few miles yesterday. Kids are staying with their Grandparents in Devon at the moment, so I actually persuaded Mrs Enforcer to come out for a drive - first time ever .

 

This was a mistake.

 

Having spent over two years resenting every penny and hour I have spent on the car she has now realised what the fuss was all about. Numbed from her enthusiasm I even agreed to let her have a drive. I'm afraid she enjoyed that too. I phoned my son (who up to now has been my only '2B Buddy'). He was gutted!

 

So when are you building her a Hood then?