Printable Version | Subscribe | Add to Favourites
New Topic New Reply
Author: Subject: Rear brakes binding
Jcb198

posted on 30/9/18 at 10:08 PM Reply With Quote
Rear brakes binding

Any one got any ideas why my rear disks on my mk woukdvsuddenly bind on. Came home approx 10 miles and when I got back I could smell the rear pads had been binding and the wheels were pretty warm. The brake pedal was rock hard with no travel. Fronts where fine. Checked the hand brake and it was off. Once cooled the pedal moves a little again and they are not binding but still mot right. I'm assuming as only the backs it probably the break bias gone bad now allowing the brake fluid to flow back to the master cylinder. It's a standard sierra master cylinder. Any one got any ideas before I hear things apart. Also anyone no what part the brake bias is.

Cheers
Jon

View User's Profile View All Posts By User U2U Member
CosKev3

posted on 30/9/18 at 11:27 PM Reply With Quote
Could your rod from pedal into MC be slightly too long?
View User's Profile View All Posts By User U2U Member
Jcb198

posted on 1/10/18 at 06:04 AM Reply With Quote
It's something new as done over 400 miles these last few weeks and has been till now so it's like something has start to fail but just not sure what.
View User's Profile View All Posts By User U2U Member
JAG

posted on 1/10/18 at 09:05 AM Reply With Quote
If you're using the standard Sierra Master Cylinder what sort of device is the 'brake bias' that you mention?

Did this part also come from a Sierra?

Is it screwed into the port of the Master Cylinder?

Is it a separate device plumbed into the brake pipes somewhere?

Got any pictures?

[Edited on 1/10/18 by JAG]





Justin


Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!

View User's Profile E-Mail User View All Posts By User U2U Member
Jcb198

posted on 1/10/18 at 10:11 AM Reply With Quote
I'll get a pic this evening. It's mounted in rear axle the brake line comes from the front of car into this then splits in two left and right rear brake lines. It has a plunger on top with a bolt that screws down onto it.im assuming to adjust the pressure.do not know where it's from I didn't build the car.
View User's Profile View All Posts By User U2U Member
JAG

posted on 1/10/18 at 10:51 AM Reply With Quote
Like this?








Justin


Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!

View User's Profile E-Mail User View All Posts By User U2U Member
davew823

posted on 1/10/18 at 11:11 AM Reply With Quote
Rear brakes

Check the clearance on the push rod on the master cylinder. You need 1mm of free play between the push rod the piston, to allow the return port to open. Are you using a pedal return spring?
If that does not solve the problem you will have to strip down and inspect the rear brakes. Davew823

View User's Profile E-Mail User View All Posts By User U2U Member
Jcb198

posted on 1/10/18 at 11:25 AM Reply With Quote
No I'm not using a return spring.ill take the plunger out tonight see if that helps but fairly certain that's all fine as nothing has changed.i have checked for stones etc stopping the piston fully returning. Plus the fronts are fine so the return port is opening in that. What amount the return port on the rear circuit being blocked that could be an option. The pedal fully returned but was rock solid almost as if there was too much fluid in the lines but that can not be possible can it?
View User's Profile View All Posts By User U2U Member
nick205

posted on 1/10/18 at 02:52 PM Reply With Quote
What state are the rear brake calipers in?

Any chance (if they're floating) that the sliders and siezed or even that the pistions themselves are not returning as they should?

If the calipers aren't working correctly they may not be releasing pressure from the brake pads and causing them to bind against the discs.

View User's Profile Visit User's Homepage View All Posts By User U2U Member
Jcb198

posted on 1/10/18 at 02:58 PM Reply With Quote
Calipers look good iv not pulled them yet however. I doubt both could have failed at the same time.must be something to do with master cylinder or break bias unit. I'm going to release the pressure via the bleed nipple and see if the calipers back off. That will prove calipers are good
View User's Profile View All Posts By User U2U Member
nick205

posted on 1/10/18 at 03:23 PM Reply With Quote
Sensible approach.

Removing the bias adjuster from the system would identify whether that is at fault as well. Would mean topping up and bleeding the brakes, but you're most likely going to have to do that at some point anyway.

View User's Profile Visit User's Homepage View All Posts By User U2U Member
black fingernail
Contributor






Posts 144
Registered 2/7/09
Location devon
Member Is Offline

Photo Archive Go!
Building: finished? scratch built book locost with 1700 puma

posted on 1/10/18 at 07:02 PM Reply With Quote
Is the handbrake cable(s) & mechanism free and actually releasing at the hubs ?
View User's Profile E-Mail User View All Posts By User U2U Member
Mike Bentley

posted on 1/10/18 at 07:10 PM Reply With Quote
brake bind

I would say not enough clearance on the brake rod to the rear master cylinder
View User's Profile View All Posts By User U2U Member
Jcb198

posted on 1/10/18 at 08:02 PM Reply With Quote
Problem solved. I'm taking the carpet put of the foot well I noticed a washed was stuck under the brake pedal stopping it returning fully. I opened the bleed nipple on the rear to allow the pedal to be pressed so I could remove the trapped washer
View User's Profile View All Posts By User U2U Member
nick205

posted on 2/10/18 at 09:30 AM Reply With Quote
Always best when it's the simple things

Well done for checking before dismatling the braking system.

View User's Profile Visit User's Homepage View All Posts By User U2U Member

New Topic New Reply


go to top






Website design and SEO by Studio Montage

All content 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [ 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.