Brakes bleeding
Discussion
Hello guys,
After a quick search on this forum, it seems that I've a problem, I can't correctly bleed my 350 brakes.
After many attempt following "old fashion" method (ie pedal pumping), I still have an excessive pedal travel, so might still have some air trapped somewhere.
The BMC, calipers, flexibles and pipes are in very good condition, but I don't understand what is the sort of brake limiter or balance valve who's bolted on the inner wing, not far from the BMC.
It seems to be on the car from new, not a modification : any idea about what it can be ?
I've a rendez-vous later today with a friend, we'll try to pressure bleeding the system.
After a quick search on this forum, it seems that I've a problem, I can't correctly bleed my 350 brakes.
After many attempt following "old fashion" method (ie pedal pumping), I still have an excessive pedal travel, so might still have some air trapped somewhere.
The BMC, calipers, flexibles and pipes are in very good condition, but I don't understand what is the sort of brake limiter or balance valve who's bolted on the inner wing, not far from the BMC.
It seems to be on the car from new, not a modification : any idea about what it can be ?
I've a rendez-vous later today with a friend, we'll try to pressure bleeding the system.
chris59 said:
I've a rendez-vous later today with a friend, we'll try to pressure bleeding the system.
... I'd be lost without mine
Don't know what the bias valve looks like on a Wedge but on my S it is a definite "high point", there is no bleed nipple so I bleed by loosening the outlet connection and plenty of rag around it.
I also have a Gunson, but won't spent my time at crawling under the car/rain on my drive anymore....
Back from my friend's garage, Tasmin on the 2 post lift, where I spent some time at trying to find what's wrong : all system pressure bleed now, but there was no air in the system, so the excessive pedal travel problem will find his source elsewhere.
The sort of valve is connected in line to only one (front or rear, I don't know) circuit, imho it's him or the -apparently perfect !- BMC who is the culprit.
Could it be Something like in a Mini, ie with a small steel ball Inside the sort of valve ?
One important point : this cars stood without moving for nearly 3 years, and I've checked the BMC internals (as new !) and none of the calipers are leaking/rusted/sized.
Any thoughts, dear Wedge owners ?
Back from my friend's garage, Tasmin on the 2 post lift, where I spent some time at trying to find what's wrong : all system pressure bleed now, but there was no air in the system, so the excessive pedal travel problem will find his source elsewhere.
The sort of valve is connected in line to only one (front or rear, I don't know) circuit, imho it's him or the -apparently perfect !- BMC who is the culprit.
Could it be Something like in a Mini, ie with a small steel ball Inside the sort of valve ?
One important point : this cars stood without moving for nearly 3 years, and I've checked the BMC internals (as new !) and none of the calipers are leaking/rusted/sized.
Any thoughts, dear Wedge owners ?
When my master cylinder failed it kept admitting air at the top, no end of bleeding would fix it because it let more in. So that might be your problem. No point rebuilding these get a new one (cortina Mk IV as I recall but check the number of exit pipes against your one.)
Edited by adam quantrill on Thursday 22 March 20:18
I've had to rebuild my front brakes due to seizing pistons which involved splitting the two halves. I couldn't get rid of the air out of them when re-assembled even with a Gunson. In the end I removed them from the car but kept the flexible brake lines attached, turned the Gunson on and bled them turning them upside down and around . Then re-assembled back on the car and all was good. Bit messy though.
SLB said:
I've had to rebuild my front brakes due to seizing pistons which involved splitting the two halves. I couldn't get rid of the air out of them when re-assembled even with a Gunson. In the end I removed them from the car but kept the flexible brake lines attached, turned the Gunson on and bled them turning them upside down and around . Then re-assembled back on the car and all was good. Bit messy though.
That's very interesting, SLB : what made me initially think about an air trap was that the fluid wasn't getting out of both bleed nipples under the same pressure.Albeit the pedal travel is rather excessive, the brakes seems to be working correctly, so a rendez-vous is taken this Monday for a "contrôle technique" (our MOT) : with some luck, the force applied by the tester on the brakes during the test may reveal something...
Remove the front pads replace with a flat bar. Pump the pedal a few times,being careful not to pop the piston. Crack the joint.use an adjustable spanner to push in the piston with a rag covering the joint. Ensure the bar edge is in the middle of the piston. Tighten the joint. Job done.repeat as necessary.
If it's just too much travel there is an adjustment from the master cylinder to the pedal. Be careful not to over adjust it as the brakes will be permanently on.
I think the valve you are describing is to stop the back brakes locking up under heavy breaking. It should be connected in the line from the mater cylinder to the back brakes.
Cheers Steve
I think the valve you are describing is to stop the back brakes locking up under heavy breaking. It should be connected in the line from the mater cylinder to the back brakes.
Cheers Steve
Thanks for the tips guys !
Back from the "contrôle technique", passed with flying colours, yeepee !!
The brakes, albeit with an excessive travel, performed really well, they do not need pumping at all, so it's not an air lock problem.
SEvan may have a point : when I've checked the brake master cylinder (almost new Inside), I decide to paint it (the outside, hey !) with a good anti rust black paint.
I can't remember if I applied some paint on the face who mate the brake servo, but, if yes, the thickness of this paint (rather thick, believe me) may increase the pedal travel, as the pushrod will be more far from the piston.....
If this is the problem, I really deserve a kick !
Back from the "contrôle technique", passed with flying colours, yeepee !!
The brakes, albeit with an excessive travel, performed really well, they do not need pumping at all, so it's not an air lock problem.
SEvan may have a point : when I've checked the brake master cylinder (almost new Inside), I decide to paint it (the outside, hey !) with a good anti rust black paint.
I can't remember if I applied some paint on the face who mate the brake servo, but, if yes, the thickness of this paint (rather thick, believe me) may increase the pedal travel, as the pushrod will be more far from the piston.....
If this is the problem, I really deserve a kick !
Gassing Station | Wedges | Top of Page | What's New | My Stuff