Main IndexAuto Repair Home Search Posts SEARCH
POSTS
Who's Online WHO'S
ONLINE
Log in LOG
IN









Haunted Brakes


Search for (search options)
 



welshman
New User

Jul 29, 2012, 11:31 AM

Post #1 of 5 (1729 views)
Haunted Brakes Sign In

Another one and this is for the best mechanics as it has been into every shop including several ford dealers. I have a 1984 f150 and in the winter it is a death trap as the front brakes lock up. The rear brakes will not lock up or apply enough pressure. Stand on the brakes when stopped and hit the gas and the rear wheels will break free. Here is what has been done. new brakes, linings, (3 times) wheel cylinders 2 times, brake lines (all) equalization valve and centered, new master cylinder, new vacumn booster with push rod and pushrod set at the correct depth. Front brakes serviced and checked. Everything that can be replaced has been. Even brakes that are working came off another truck and installed and still the same.
Ford dealer said if they cannot fix it there will be no charge at all. They changed the rear brakes to heavy duty larger lining and wheel cyclinders, redid ALL THE ABOVE, check for air, checked all fittings. Then onto the hoist, rev the engine, hold the brakes hard and still the rears turn under power. They actually said the truck was cursed and to get it out of the shop and only drive in the summer ....l.o.l. So any help out there on this one.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 29, 2012, 11:45 AM

Post #2 of 5 (1715 views)
Re: Haunted Brakes Sign In

My guess is that the truck was built with a brake package combination that wasn't really compatible. They just gave it more front brake capability than the rear can handle. It would probably have to be modified in some way to correct the issue. Maybe convert the rear to disc.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 29, 2012, 12:45 PM

Post #3 of 5 (1690 views)
Re: Haunted Brakes Sign In

Quote">>Even brakes that are working came off another truck and installed and still the same.<<"

Not a real fan of that. 1984 is almost certainly pre antilock anything but could have this proportioning valve wrong and now sizing of rear altered??

Open to lots of maybes IMO but will toss in "are rear shoes" reversed meaning the one with more lining on the front? That alone would do that. Should be same metal and different lining length or % covering the shoe. Just a wild "haunted" guess that might have been missed??

T



nickwarner
Veteran / Moderator
nickwarner profile image

Jul 29, 2012, 8:10 PM

Post #4 of 5 (1660 views)
Re: Haunted Brakes Sign In

Tom might be onto something here. I learned to drive on the same truck you have. They used two different lengths of lining per wheel. It was called the leading shoe and trailing shoe. Get them mixed up and you will have ineffective rear braking. The techs at Ford that get the chassis and brake issues are likely junior techs and it is very rare to them to even see a drum brake in person, much less one as old or older than themselves. Is this an inboard drum or outboard? Can you get the drum off to show us a pic of how the linings are currently installed?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 30, 2012, 12:23 AM

Post #5 of 5 (1652 views)
Re: Haunted Brakes Sign In

Simple test and lifelong observation of "ordinary" drum brakes. The leading shoe does little as it is really jamming the trailing shoe against the anchor pin so they make more lining for that shoe.

Note that you can set a cable parking brake (that uses the service brakes) firmly and back up without much trouble on almost all of these and then go forward it feels like it's welded to the ground!

Could something like that be missed by several techs. YES because it would look normal at a glance. Asymmetrically opposite if you like a big word (mirror image to save you looking that up) --

Tom







 
 
 






Search for (options) Privacy Sitemap