No brake pressure after rebuild....
Discussion
Hi
Over the past year or so I have carried out a pretty much nut and bolt restoration on a MK3 Fiesta RS Turbo.
I have learnt all the relevant skills myself and even sprayed it myself after buying the gear.
I started it for the first time this week using a rebuilt engine.
For the past couple of days I have been trying to bleed the brakes; without joy.
I have new brake pipes, new hoses, new discs, new callipers, new shoes and fittings.....
The only thing that is not new is the master cylinder.
I began on Thursday and purchased a Gunson pressure bleeding kit. I connected it all up and am getting plenty of fluid from each nipple. Naturally with new lines there was some air in the beginning but this very quickly dissapeared.
I have tried about 10 times now to bleed the system with no joy. The brake pedal can be pushed all the way to the floor. I have been bleeding with the engine off.
I suspected the master cylinder to be at fault so stripped it down yesterday and replaced the internals with another old master cylinder that I had lying around. Admittedly both master cyclinders are not new. The next option will be to buy a new one and try again....
As I say I am getting fluid flowing from each bleed nipple. I have let a lot run through; sometimes as much as nearly a pint of fluid in total from the 4 corners. I have tried bleeding in a different sequences etc, nothing seems to work.
With the engine on or off the pedal can be pushed to the floor.
What am i missing??
The system is not complex. It is non-ABS. The servo - the master cylinder- the front wheels- the rears go via a pressure reducing unit to back wheels but this would not bring about the above.
I also removed one of the 4 brake lines at the master cylinder in the begininng incase thare was air in there.
Any help would be superb as I am banging my head against a very hard wall....
Cheers
Over the past year or so I have carried out a pretty much nut and bolt restoration on a MK3 Fiesta RS Turbo.
I have learnt all the relevant skills myself and even sprayed it myself after buying the gear.
I started it for the first time this week using a rebuilt engine.
For the past couple of days I have been trying to bleed the brakes; without joy.
I have new brake pipes, new hoses, new discs, new callipers, new shoes and fittings.....
The only thing that is not new is the master cylinder.
I began on Thursday and purchased a Gunson pressure bleeding kit. I connected it all up and am getting plenty of fluid from each nipple. Naturally with new lines there was some air in the beginning but this very quickly dissapeared.
I have tried about 10 times now to bleed the system with no joy. The brake pedal can be pushed all the way to the floor. I have been bleeding with the engine off.
I suspected the master cylinder to be at fault so stripped it down yesterday and replaced the internals with another old master cylinder that I had lying around. Admittedly both master cyclinders are not new. The next option will be to buy a new one and try again....
As I say I am getting fluid flowing from each bleed nipple. I have let a lot run through; sometimes as much as nearly a pint of fluid in total from the 4 corners. I have tried bleeding in a different sequences etc, nothing seems to work.
With the engine on or off the pedal can be pushed to the floor.
What am i missing??
The system is not complex. It is non-ABS. The servo - the master cylinder- the front wheels- the rears go via a pressure reducing unit to back wheels but this would not bring about the above.
I also removed one of the 4 brake lines at the master cylinder in the begininng incase thare was air in there.
Any help would be superb as I am banging my head against a very hard wall....
Cheers
Are you able to expel fluid from an open nipple the old fashioned way, without pressuring the system with a bleed kit? Ie is the m/c moving fluid at all?
Does the system 'pump up' with repeated pedal presses to compress any air in the system?
Check m/c by using banking plugs in all ports apart from one, connect short length of brake pipe with bleed nipple on the end into the last one. Note you may need additional bleedable outlets to clear the master cylinder of air.
Are the calipers definitely on the right side of the car and therefore the right way up?
M/c is a bad component to save money on.
Does the system 'pump up' with repeated pedal presses to compress any air in the system?
Check m/c by using banking plugs in all ports apart from one, connect short length of brake pipe with bleed nipple on the end into the last one. Note you may need additional bleedable outlets to clear the master cylinder of air.
Are the calipers definitely on the right side of the car and therefore the right way up?
M/c is a bad component to save money on.
Thanks for the reply!
Ok, Point by point:
Funny you should mention the old fashioned way. On Thursday as I say I wanted to sort the brakes, I knew I had an oid one-man easy bleed kit so found it and put the car up on stands. I started on the furthest wheel from the master cylinder (MS) and opened the bleed nipple whilst I got my partner to pump the brake pedal. For some reason after a few pumps of the pedal it became clear that the fluid was not entering the clear tube. Fluid was though reaching the nipple as some leaked out. I naturally came to the conclusion that the bleeding kit was at fault as it was dirty and old.
Constant pumping of the pedal is building absolutely no pressure in thg system and this is where the fault lies. Engine on or off; no pressure is building under the pedal.
The callipers are definately on the correct way.
The one time I had the pressure kit connected up and went to pump the brake pedal by mistake as I forgot to remove it. The pedal then felt good; hence when pressuirised by the spare tyre.
What does all this point to? The lack of pressure in the system and the inability to build pressure even though fluid is reaching the nipples?
Could it be a part of the system has been put back together incorrectly?? It all looks correct.
Thanks again
Check m/c by using banking plugs in all ports apart from one, connect short length of brake pipe with bleed nipple on the end into the last one. Note you may need additional bleedable outlets to clear the master cylinder of air.
Are the calipers definitely on the right side of the car and therefore the right way up?
M/c is a bad component to save money on.
[/quote]
Ok, Point by point:
Funny you should mention the old fashioned way. On Thursday as I say I wanted to sort the brakes, I knew I had an oid one-man easy bleed kit so found it and put the car up on stands. I started on the furthest wheel from the master cylinder (MS) and opened the bleed nipple whilst I got my partner to pump the brake pedal. For some reason after a few pumps of the pedal it became clear that the fluid was not entering the clear tube. Fluid was though reaching the nipple as some leaked out. I naturally came to the conclusion that the bleeding kit was at fault as it was dirty and old.
Constant pumping of the pedal is building absolutely no pressure in thg system and this is where the fault lies. Engine on or off; no pressure is building under the pedal.
The callipers are definately on the correct way.
The one time I had the pressure kit connected up and went to pump the brake pedal by mistake as I forgot to remove it. The pedal then felt good; hence when pressuirised by the spare tyre.
What does all this point to? The lack of pressure in the system and the inability to build pressure even though fluid is reaching the nipples?
Could it be a part of the system has been put back together incorrectly?? It all looks correct.
Thanks again
Check m/c by using banking plugs in all ports apart from one, connect short length of brake pipe with bleed nipple on the end into the last one. Note you may need additional bleedable outlets to clear the master cylinder of air.
Are the calipers definitely on the right side of the car and therefore the right way up?
M/c is a bad component to save money on.
[/quote]
Tricky.
I do know what I would do as next step though....
The money and love you have so far invested project will only be enhanced by the addition if a sparkly new m/c. It will rule this component out if the problem still exists and allow you to focus elsewhere on the system. Hopefully it will fix it, but even if not, for such a vital component, at such a reasonable price, why not swap for new?
I do know what I would do as next step though....
The money and love you have so far invested project will only be enhanced by the addition if a sparkly new m/c. It will rule this component out if the problem still exists and allow you to focus elsewhere on the system. Hopefully it will fix it, but even if not, for such a vital component, at such a reasonable price, why not swap for new?
Surprised no-one has mentioned this yet. Do not rule out the possibility that the problem is air getting IN to the fluid, I have seen this occur in two ways;
- badly worn bleed nipple was not seating properly on the sealing surface in the caliper.
- master cylinder reservoir had a hairline crack where it joined the cylinder itself.
- badly worn bleed nipple was not seating properly on the sealing surface in the caliper.
- master cylinder reservoir had a hairline crack where it joined the cylinder itself.
HustleRussell said:
Surprised no-one has mentioned this yet. Do not rule out the possibility that the problem is air getting IN to the fluid, I have seen this occur in two ways;
- badly worn bleed nipple was not seating properly on the sealing surface in the caliper.
- master cylinder reservoir had a hairline crack where it joined the cylinder itself.
Hi- badly worn bleed nipple was not seating properly on the sealing surface in the caliper.
- master cylinder reservoir had a hairline crack where it joined the cylinder itself.
I am using new callipers and new cylinders on the rear.
Think I will buy a new master cylinder next week.
It would not make any difference would it if I jack up one corner at a time and try this way instead of having it raised in the air?
Yuxi said:
Have you adjusted the rear brakes properly? I assume they are drums as you mentioned new cylinders being used.
HiThe rear drums are self adjusting; works on a cam I think.
Even if there was an adjustment issue surely the fronts would work?
I am going to order a new master cylinder tomorrow I think.
I will double check all connections are tight but surely even if one was not tight then fluid would be pouring out when the pressure kit is put on.
Thanks
Hi
A new master cylinder arrived yesterday. I fitted it before putting the car on stands once again.
I tried the pressure bleeding kit first but no joy. The same thing happened; the pedal is too soft and with force can just about be pushed to the floor.
All bleeding is being done with the engine off.
I then decided to try the one man brake kit. So that I could make sure fluid was flowing through the system properly I got someone to pump the brake pedal for me.
This time the pedal did firm up a little bit and to be honest I was sure I would have some braking.
Put the wheels back on and dropped the car to the floor but unfortunately the brakes are virtually non-existent.
Now I know I will get told off for this but whilst I always planned on just getting it quickly set up now and would be changing the brake fluid very soon, I have been using old brake fluid.
It is a large bottle (prob 2.5l) of brake/clutch fluid that has been opened for about 5 years....
Now when I studied the fluid yesterday, for example when I drew some out of the master cylinder with a syringe, it appears to be full of tiny, tiny air bubbles.
I will stop on my way home from work today and buy some new good quality brake fluid.
My question for now is:
Would using the old fluid bring about the problems that I have been facing??
Thanks
A new master cylinder arrived yesterday. I fitted it before putting the car on stands once again.
I tried the pressure bleeding kit first but no joy. The same thing happened; the pedal is too soft and with force can just about be pushed to the floor.
All bleeding is being done with the engine off.
I then decided to try the one man brake kit. So that I could make sure fluid was flowing through the system properly I got someone to pump the brake pedal for me.
This time the pedal did firm up a little bit and to be honest I was sure I would have some braking.
Put the wheels back on and dropped the car to the floor but unfortunately the brakes are virtually non-existent.
Now I know I will get told off for this but whilst I always planned on just getting it quickly set up now and would be changing the brake fluid very soon, I have been using old brake fluid.
It is a large bottle (prob 2.5l) of brake/clutch fluid that has been opened for about 5 years....
Now when I studied the fluid yesterday, for example when I drew some out of the master cylinder with a syringe, it appears to be full of tiny, tiny air bubbles.
I will stop on my way home from work today and buy some new good quality brake fluid.
My question for now is:
Would using the old fluid bring about the problems that I have been facing??
Thanks
Start by clamping off all the flexi hoses if the pedal goes hard you know its a problem other than the master cylinder then remove the clamps one at a time when the pedal goes you know which corner is causing your woe.
If the clamps dont work then i would work from the master pipe connections bleeding at each joint as you go & hopefully will get you there although using old fluid is a big no!!
On the fiestas the brake limiting valve can sometimes get stuck & this can cause issues bleeding out so also worth checking this considering it has been sitting for quite some time.
If the clamps dont work then i would work from the master pipe connections bleeding at each joint as you go & hopefully will get you there although using old fluid is a big no!!
On the fiestas the brake limiting valve can sometimes get stuck & this can cause issues bleeding out so also worth checking this considering it has been sitting for quite some time.
neiljohnson said:
Start by clamping off all the flexi hoses if the pedal goes hard you know its a problem other than the master cylinder then remove the clamps one at a time when the pedal goes you know which corner is causing your woe.
If the clamps dont work then i would work from the master pipe connections bleeding at each joint as you go & hopefully will get you there although using old fluid is a big no!!
On the fiestas the brake limiting valve can sometimes get stuck & this can cause issues bleeding out so also worth checking this considering it has been sitting for quite some time.
Thanks for the reply.If the clamps dont work then i would work from the master pipe connections bleeding at each joint as you go & hopefully will get you there although using old fluid is a big no!!
On the fiestas the brake limiting valve can sometimes get stuck & this can cause issues bleeding out so also worth checking this considering it has been sitting for quite some time.
Unfortunately the hoses are braided so they will not clamp.
Also the master cylinder is brand new so we know this is not at fault.
When you say 'brake limiting valve' do you mean the one on the front inner wing? The valve located here is a pressure valve that compensates for the extra distance that the fluid has to travel to the back brakes.
This is the only valve on the system as the load valves at the rear of the car have been removed.
I will definately pick up the new fluid on my way home but I am not confident!
Before I start I will check once again all connections. I know there is no fluid leaking out but could there still be some air getting in?
The pedal feel did definately improve some what after trying the one man bleeding kit; although I had no brakes!
Purchased new brake fluid and attempted to pressure bleed system again.
Exactly the same, pedal and virtually be pushed to the floor.
When I connected the pressure system I opened up the 4 x connections on the master cyclinder to get rid of any air and also did the 4 x connection on the vlave on the inner wing.
Got no idea....
Going to re-read the instructions for the kit incase I am doing something daft.
Exactly the same, pedal and virtually be pushed to the floor.
When I connected the pressure system I opened up the 4 x connections on the master cyclinder to get rid of any air and also did the 4 x connection on the vlave on the inner wing.
Got no idea....
Going to re-read the instructions for the kit incase I am doing something daft.
Update..
Even though the brake pedal is soft I got someone to hold the pedal down this morning whilst the car was on stands.
With the pedal pressed I attempted to move each wheel. Both front wheels were held meaning the callipers are operating ok. The drivers side rear was held by the brake but the passenger side rear was not.
I removed the nsr drum and the inside of it and the shoes were covered with black brake fluid!!
The cylinders are brand new...
The cylinder must have been leaking contaminating the shoes hence the black fluid.
I also removed the nsr and all was dry.
This means air would be getting into the system as well as fluid getting out.
Would this definately cause the problems I have been experiencing?? I guess so.
Even though the brake pedal is soft I got someone to hold the pedal down this morning whilst the car was on stands.
With the pedal pressed I attempted to move each wheel. Both front wheels were held meaning the callipers are operating ok. The drivers side rear was held by the brake but the passenger side rear was not.
I removed the nsr drum and the inside of it and the shoes were covered with black brake fluid!!
The cylinders are brand new...
The cylinder must have been leaking contaminating the shoes hence the black fluid.
I also removed the nsr and all was dry.
This means air would be getting into the system as well as fluid getting out.
Would this definately cause the problems I have been experiencing?? I guess so.
TROOPER88 said:
Update..
Even though the brake pedal is soft I got someone to hold the pedal down this morning whilst the car was on stands.
With the pedal pressed I attempted to move each wheel. Both front wheels were held meaning the callipers are operating ok. The drivers side rear was held by the brake but the passenger side rear was not.
I removed the nsr drum and the inside of it and the shoes were covered with black brake fluid!!
The cylinders are brand new...
The cylinder must have been leaking contaminating the shoes hence the black fluid.
I also removed the nsr and all was dry.
This means air would be getting into the system as well as fluid getting out.
Would this definately cause the problems I have been experiencing?? I guess so.
That will be the issue then!Even though the brake pedal is soft I got someone to hold the pedal down this morning whilst the car was on stands.
With the pedal pressed I attempted to move each wheel. Both front wheels were held meaning the callipers are operating ok. The drivers side rear was held by the brake but the passenger side rear was not.
I removed the nsr drum and the inside of it and the shoes were covered with black brake fluid!!
The cylinders are brand new...
The cylinder must have been leaking contaminating the shoes hence the black fluid.
I also removed the nsr and all was dry.
This means air would be getting into the system as well as fluid getting out.
Would this definately cause the problems I have been experiencing?? I guess so.
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