No brakes after rebuild (well still no brakes.....)
Discussion
Hi
I posted a few weeks ago regarding the fact that I have carried out a nut and bolt restoration on a mk3 Fiesta RS Turbo, and unfortunately I can not get the brake pedal to firm up.
I updated the last thread stating that I removed the one rear drum and found the cylinder was leaking badly. I thought and hoped that this was the problem but it wasn't.
To clarify the callipers are refurbished units, the discs, pads, cylinder, pipe works, hoses and master cylinder are all brand new.
I have tried pressure bleeding and the old fashioned way.
This morning I went around and made sure all the connections were tight.
I then set the spare wheel up again and tried pressure bleeding once more.
I followed the correct sequence and to be honest this time little or no air at all came out of the nipples; just clean fluid.
I am making sure that I take quite a lot of fluid out of each corner to ensure that any air is removed.
I am doing this process and then trying the pedal all without the engine running.
I have totally removed the ABS system that was on the car so the system now comprises of the servo, the master cylinder and a valve unit on the inner wing which just ensures that the rear brakes get the same amount of pressure as the fronts.
Still the pedal does not firm up, with a little effort it can just about be pressed to the floor. Some have mentioned that it sounds like air is somehow getting into the system.
I have not totally dismissed this but if this was/is the case would I not see this air being expelled when bleeding??
I am now beginning to think that maybe a mechanical part of the system has be been reassembled incorrectly; I do not know what but I just do not understand why I am not getting brakes.
I did fit a second hand servo. Even without the car running if this was defective could the mechanics of it give me issues?
I am getting a nice flow of fluid from each corner when I bleed.
Any help as I am sure you can gather will be greatly received!
Thank you
I posted a few weeks ago regarding the fact that I have carried out a nut and bolt restoration on a mk3 Fiesta RS Turbo, and unfortunately I can not get the brake pedal to firm up.
I updated the last thread stating that I removed the one rear drum and found the cylinder was leaking badly. I thought and hoped that this was the problem but it wasn't.
To clarify the callipers are refurbished units, the discs, pads, cylinder, pipe works, hoses and master cylinder are all brand new.
I have tried pressure bleeding and the old fashioned way.
This morning I went around and made sure all the connections were tight.
I then set the spare wheel up again and tried pressure bleeding once more.
I followed the correct sequence and to be honest this time little or no air at all came out of the nipples; just clean fluid.
I am making sure that I take quite a lot of fluid out of each corner to ensure that any air is removed.
I am doing this process and then trying the pedal all without the engine running.
I have totally removed the ABS system that was on the car so the system now comprises of the servo, the master cylinder and a valve unit on the inner wing which just ensures that the rear brakes get the same amount of pressure as the fronts.
Still the pedal does not firm up, with a little effort it can just about be pressed to the floor. Some have mentioned that it sounds like air is somehow getting into the system.
I have not totally dismissed this but if this was/is the case would I not see this air being expelled when bleeding??
I am now beginning to think that maybe a mechanical part of the system has be been reassembled incorrectly; I do not know what but I just do not understand why I am not getting brakes.
I did fit a second hand servo. Even without the car running if this was defective could the mechanics of it give me issues?
I am getting a nice flow of fluid from each corner when I bleed.
Any help as I am sure you can gather will be greatly received!
Thank you
Having exactly the same issue on my XI, just can't get a firm pedal. Calipers are rebuilt, new rear cylinders, new copper pipe, new braided hoses, new pads and shoes, calipers fitted the correct way round (nipples up), rear shoes adjusted. No joy, I can only assume I have an extremely stubborn air bubble somewhere.
Youre gonna laugh at this tip, but here goes.
depress brake pedal as hard as you can, and chock with big stick or similar between pedal and seat base frame to simulate brakes being firmly on.
leave overnight with brake pedal jammed firmly on.
next morning (or at least 6/8hrs) remove big stick and try brakes again.
I will bet you that if its a stubborn airlock, the problem will be gone!!
i know it sounds b
ks, but its worked for me dozens of times on road and racers alike.
try it and report back.
CNH
depress brake pedal as hard as you can, and chock with big stick or similar between pedal and seat base frame to simulate brakes being firmly on.
leave overnight with brake pedal jammed firmly on.
next morning (or at least 6/8hrs) remove big stick and try brakes again.
I will bet you that if its a stubborn airlock, the problem will be gone!!
i know it sounds b
ks, but its worked for me dozens of times on road and racers alike.try it and report back.
CNH
CNHSS1 said:
Youre gonna laugh at this tip, but here goes.
depress brake pedal as hard as you can, and chock with big stick or similar between pedal and seat base frame to simulate brakes being firmly on.
leave overnight with brake pedal jammed firmly on.
next morning (or at least 6/8hrs) remove big stick and try brakes again.
I will bet you that if its a stubborn airlock, the problem will be gone!!
i know it sounds bks, but its worked for me dozens of times on road and racers alike.
try it and report back.
CNH
Thanks. I will definately try and report back!depress brake pedal as hard as you can, and chock with big stick or similar between pedal and seat base frame to simulate brakes being firmly on.
leave overnight with brake pedal jammed firmly on.
next morning (or at least 6/8hrs) remove big stick and try brakes again.
I will bet you that if its a stubborn airlock, the problem will be gone!!
i know it sounds b
ks, but its worked for me dozens of times on road and racers alike.try it and report back.
CNH
The problem is when the engine is OFF the brake pedal DOES NOT firm up and go hard.
I know for a fact that with engine off the pedal should go rock hard after a few presses; this is simply not happening.
I wondering whether to pop to local scrap yard and try and salvage a second hand servo but guess I should at least try above first.
If there was a air lock within the pipe work surely I would not get a good flow of fluid from the nipple??
Xtriple129 said:
When the calipers were rebuilt/replaced, you didn't put them back on the wrong sides, you know, with the bleed nipples low as opposed to on the top? Makes a hell of a difference if you did.
No, bleed nipples are on the top on both sides.I am going to take some pictures later and add them to this thread.
Air can be a right pain to get out of the plumbing - in the routing of the brake lines are there any kinks, high points (don't have to be too obvious, attention to detail is key) or sharp corners that the lines follow? Tapping the M/C with a rubber mallet and shake from some air bubbles too.
Check for perfect sealing around all the joins too - some leaks won't be obvious so get up close with a torch and look for signs of leakage.
Check for perfect sealing around all the joins too - some leaks won't be obvious so get up close with a torch and look for signs of leakage.
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