No Brakes!!

[Lost_Cause]

Hey. Been stumped for a while now coz my car doesn't stop. I've replaced most of the set-up, but the brakes feel like they're suffering from brake fade from a hard thrash, but that's from cold without even moving the car. Here's a list of what i've done so someone can see where i'm going wrong:
Brembo 239mm grooved discs- Pagid fast road pads- 22mm master cylinder- Dot 4 mintex fluid- New compensator/ bias valve from GSF- new rear brake cylinders- shoes are ok- fully bled system........same result! No change.
Some people have said change the servo but it's €320 & may not solve the problem.
Others have said adjust the compensator, but there's not even braking power up front,never mind out back.
I'm suspect that it may be something to do with the vacuum lines, because i have a running problem that i think is related.
When the engine has warmed up (after 10mins or so of idling), it's revs drop away slowly until the engine splutters & struggles to stay running & then cuts out. It's not the timing because i've advanced it a titch so she idles about 1100rpm. It also happens when driving, there's just a drop in power & i need to change down or dip the clutch & give a little blip of throttle while the clutch is depressed.
Also, i think i got sold a set of standard rear cylinders, instead of g40 spec. how much would this contribute, if any, to the problem?
Any help would be hugely appreciated because due to the damned recession,i haven't the money to pay an expert to check over it.
Cheers lads.

[PeteG40]

how old are the brake discs/pads?  if they are new they are shocking and need 3-500 miles to bed in. otherwise they do feel  like fading brakes

[samg40]

Sorry to hijack, but how much was the compensator from GSF please?

I am about to change the servo on my car because it feels like there are two stages to my brake pedal. They are around £30 from euro car parts apparently.

[PeteG40]

£52.50+vat from gsf

[tdh-syorks]

gotta change my servo too, its propa knackd, who needs brakes anyway?

[scotsjohn]

Sounds like the shoes are standing off the drums quite a bit. There goes most of your pedal travel and you get the "two stage effect". Make sure you have the self-adjuster wedges driven down to the point that you can just get the rear drums on. "Self Adjusting" drums mean just that on VWs; you have to adjust them yourself every couple of thousand miles. A slightly stronger spring on the wedges would help if you can find one. Failing that, Demon Tweeks sell dudey little in-line valves that stop the shoes dropping back too far.

[PeteG40]

if your on about sam's car - it has new shoes, drums, bearings, cylinders, hoses and mastercylinder and are well adjusted

[Lost_Cause]

Thanks for all the advice.
The discs & pads have about 80 miles on 'em, but the car is unstoppable really. Tried various ways of bedding them in followd by un-glazing the pads afterwards. Will have to get a better look at the rears when i can (car is at a mates 20 miles away).
Not to sound stubborn, but would the servo or the vacuum lines be responsible?? Just that if i get there & find the rears are set-up perfect, would like to know where to check!

By the way, the servo was €100 'bout 2 yrs ago,(all that's changed now with the exchange rate).
Thanks again.

[breadman]

The servo only multiplies the pedal effort, it has nothing to do with the actual hydraulic system.
You can confirm if it is working by pressing the brake pedal a few times to empty the servo "reserviour". The pedal travel should now be shorter and much firmer. Keep your foot hard on the brake pedal and start the car up. As soon as the car starts the pedal should sink down slightly and become "softer".
Now check the servo vacuum hose isn't split and that the one way valve is operating correctly (give it a blow job!). A problem here (vacuum air leak) could cause the running issues you speak about.
If you can, get the car to a garage and get them to pressure bleed the brakes. It is a far better method of bleeding the brakes, it may be that you just have air trapped in the system that is difficult to remove, particularly as you have changed the load bias valve.
The wheel cylinders are bigger bore IIRC on cars fitted with the load compensator/bias valve. If you have the smaller ones fitted, theoretically they will move the shoes out further for the same amount of fluid displacement.
Correctly adjusted, you should only have about 4 to 5 clicks on the handbrake lever. Assuming the handbrake cables are properly adjusted, more than this probably means too much brake shoe stand off.
If you find the system is hydraulically sound and the shoes are set up properly then it's probably air trapped in the system somewhere.

[samg40]

My handbrake is on fully within two clicks so that is all ok. I have pressure bled the system as I bought an ezibleed kit. Will check over the pipes although at the moment Pete has nicked my one way valve and pipe (although he did give it to me in the first place) so I've got to get hold of one of those. Car is coming out at the beginning of next month (cant wait) after its winter layup so will have another look at it all then.

What problems can the compensator cause, that and the servo are the only things that havent been changed.

[Lost_Cause]

The servo only multiplies the pedal effort, it has nothing to do with the actual hydraulic system.
You can confirm if it is working by pressing the brake pedal a few times to empty the "servo" reserviour. The pedal travel should now be shorter and much firmer. Keep your foot hard on the brake pedal and start the car up. As soon as the car starts the pedal should sink down slightly and become "softer".
Now check the servo vacuum hose isn't split and that the one way valve is operating correctly (give it a blow job!). A problem here (vacuum air leak) could cause the running issues you speak about.
If you can, get the car to a garage and get them to pressure bleed the brakes. It is a far better method of bleeding the brakes, it may be that you just have air trapped in the system that is difficult to remove, particularly as you have changed the load bias valve.
The wheel cylinders are bigger bore IIRC on cars fitted with the load compensator/bias valve. If you have the smaller ones fitted, theoretically they will move the shoes out further for the same amount of fluid displacement.
Correctly adjusted, you should only have about 4 to 5 clicks on the handbrake lever. Assuming the handbrake cables are properly adjusted, more than this probably means too much brake shoe stand off.
If you find the system is hydraulically sound and the shoes are set up properly then it's probably air trapped in the system somewhere.

Thanks breadman, got onto my mate about callin in to check over it next week. Have had the brakes pressure bled & the handbrake locks solid at 2-3 clicks. Gonna check the vacuum hose & the shoe stand-off. Little bit confused with regards the wheel cylinders, are the smaller ones better or worse. As far as memory serves me, the pedal travel is the same, ie. good pedal response. But will get onto these & let ye know how it turns out.
Donie.

[scotsjohn]

if your on about sam's car - it has new shoes, drums, bearings, cylinders, hoses and mastercylinder and are well adjusted

No Pete, that was directed to Lost-Cause

[breadman]

So to sum it up Donie you have good pedal travel, a well adjusted handbrake, a properly bled system with no obvious leaks? Mmm, I'd definately check out the servo hose and valve and carry out the servo operation check using the method I suggested.

[scotsjohn]

If your handbrakes on in a couple of clicks then the shoes will be about as close as you'll get, so no need to go there.Go with Breadman.

[GSBellew]

Hi Donie,

Sorry to hear its still giving you hassle.

I have to say I really that I think its the brake servo not doing its job.

To give others an idea of what its like, from what I remember of the brief spin I had in it last year, the pedal was hard, but the brakes just do not bite, its like standing on a brick to be honest and just about as effective