v8james
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| posted on 14/8/09 at 11:13 AM |
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Rear brake locked
I am running standard Sierra brakes, callipers and disks up front and drums on the back.
I have now fitted a bias pedal box with two cylinders 0.625 on the front and 0.75 on the back.
All the lines have been bled, fronts are working great but the rear offside drum is locking solid and will only release the wheel when I open the bled
nipple.
Thought there might be air in the rear line, but surely both drums would lock until the pressure was released.
Does anyone have any ideas?
James
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Mr Whippy
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| posted on 14/8/09 at 11:17 AM |
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yip, the hose has aged and collapsed inside effectively making a one way valve
[Edited on 14/8/09 by Mr Whippy]
Fame is when your old car is plastered all over the internet
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adithorp
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| posted on 14/8/09 at 11:27 AM |
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If it's just one side then probably as above. No play in the master cylinder push rod would also do it but probably both sides.
adrian
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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v8james
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| posted on 14/8/09 at 11:30 AM |
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Good idea, didn’t think of that.
Will replace both hoses over the weekend.
James
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britishtrident
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| posted on 14/8/09 at 01:32 PM |
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Master cylinder push rods not allowing the master cyilnder piston to fully return. --- yes I know only one caliper apears to be affected and it
appears to go against all hydraulic theory but that is what it is.
Hoses collapsing is an old wifes tale it just never happens ------
[Edited on 14/8/09 by britishtrident]
[Edited on 14/8/09 by britishtrident]
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v8james
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| posted on 14/8/09 at 01:42 PM |
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The cylinder is returning fully and pushrod is loose when brake is not applied, that’s the first thing I checked.
James
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Mr Whippy
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| posted on 14/8/09 at 02:26 PM |
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quote:
Originally posted by britishtrident
Hoses collapsing is an old wifes tale it just never happens ------
actually I had 4 that came off my beachbuggy that had collapsed and were also locking the brakes completely, couldn't even blow through them.
Were very old though, about 15 years at least and had been bent while in storage.
Fame is when your old car is plastered all over the internet
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britishtrident
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| posted on 14/8/09 at 02:36 PM |
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quote:
Originally posted by v8james
The cylinder is returning fully and pushrod is loose when brake is not applied, that’s the first thing I checked.
James
It is actually very difficult to check -- it just needs the washer that retains the pushrod in the cylinder to be the wrong washer or not beveled
correctly --- not going fully back by less than 1 mm is enough.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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rusty nuts
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| posted on 14/8/09 at 06:35 PM |
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quote:
Originally posted by britishtrident
Hoses collapsing is an old wifes tale it just never happens ------
Have to disagree , it does happen I've had several Ford Escorts in the last 5 years or so that have had a front brake locked on due to a
faulty hose.
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nz_climber
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| posted on 14/8/09 at 08:53 PM |
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Seen it on an old VW combi van, both rear hoses had collasped, no fluid could go in any direction!
http://aarons7.wordpress.com
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x_flow57
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| posted on 14/8/09 at 09:28 PM |
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Sorry but it does, I've seen it on more than one occasion, fluid passes under pedal pressure but fails to return and causes brakes to stay
on.
quote:
Hoses collapsing is an old wifes tale it just never happens ------
Nick
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adithorp
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| posted on 14/8/09 at 10:01 PM |
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I see collapsed brake hoses regularly.
adrian
ps. make the most of it boys; He's not wrong very often.  In fact before this I'd have said "It never happens"
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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v8james
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| posted on 15/8/09 at 08:41 AM |
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Replaced hoses, now works perfectly.
Seems the master cylinder was returning fully after all.
Thanks for the help Mr Whippy.
James
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britishtrident
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| posted on 15/8/09 at 03:49 PM |
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Cured ? -- we shall see.
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