North American Turbocoupe Organization



86 Turbocoupe brake problem diagnosis
rsears Offline
Member
#1
All,

Recently I thought the car had a flat tire up front because going down the highway it started pulling one to one side. I pulled over and noticed the rotor was smoking, thinking to myself "this must be a stuck caliper"

Getting back on the road, the problem subsided.

At a later date, it happened to the opposite side ending with me parking the car until I could make proper repairs.

Currently the car is up on jackstands and my initial thought was to purge the system of the old hateful looking brake fluid. Starting at the passenger rear and attempted to bleed the brakes.

I can't get any fluid out of the wheel cylinders on either side in the back. I was able to bleed the front but am wondering where the defective part must reside and if this was what was causing the erratic front brake sticking issues.

Could it be the master cylinder?

Could it be the proportioning valve?

Could it be multiple items, 1 of which is the car needing new wheel cylinders?

As far as I know, this car is all original equipment. The car only has 80k on it or so. I've never had any problems with it up until this point. I'm almost considering just doing a 87 -up fox upgrade to the front and perhaps installing a new master cylinder.

I would like to find out what needs to be replaced though rather than tossing parts at the car.

Your thoughts?
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Pete D Offline
Administrator
#2
Brake line(s) or cylinders could be plugged. There are several past posts about not being able to bleed rear brakes
Pete Dunham


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Robert Camp Offline
Posting Freak
#3
Before you do upgrades correct the current problem. The '86 is a relatively simple brake system; power boost, master cylinder, proportioning valve, front and rear brake assemblies.

Dragging on the front could be rusted up caliper pins or even a rusted piston. Check those first, my bet would be stuck caliper pins.

The rears could be; bad piston seal for the rear brakes (front reservoir on the MC) in the master cylinder, brake failure indicator piston in the proportioning valve stuck in the front or rear instead of centered, crimp in the brake line to the rear, deterioration of the rubber hose from the chassis to the rear end junction plugging the line.
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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rsears Offline
Member
#4
Pete D - I did search, however my search did not produce good results.

Robert Camp - I will probably replace the rear rubber hose and master cylinder, one of my initial thoughts now was to remove the line from the chassis and see if I can get fluid out might help diagnose bad wheel cylinders or a blockage?
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Robert Camp Offline
Posting Freak
#5
Do some checking around and then tell me where you find the flex hose for the rear end. The problem is that the junction on the axle housing is one piece with the hose. Maybe you can mode the junction box or find some aftermarket splitter that'll work.
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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rsears Offline
Member
#6
This afternoon I was finally able to make some progress on the TC. Last week I picked up a new flex hose for the chassis line to the rearend and a new MC. After some additional searching and reading about how the flex hose replacements don't fit like factory, some people used adapters or bent up new lines I wasn't sure what to expect.

I'm going to try and bleed the brakes with the original MC on tomorrow, if I get fluid out of the wheel cylinders now that means the flex hose was corroded or broken down.

Hope this post helps those in need.

Sourced Flex Hose from O`Reilly Auto Parts. The box read the following:

Brake Best Part #BH177180
Replaces DOR BH98945 & RAY BH36829

[Old hose with fitted end to axle tube atop new hose box]
http://natomessageboard.com/uploads/0000...G01187.jpg


[New Flex hose from rear to chassis bracket]

http://natomessageboard.com/uploads/0000...G01188.jpg

[New Flex hose shown with correct port locations]

http://natomessageboard.com/uploads/0000...G01189.jpg
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Robert Camp Offline
Posting Freak
#7
So it connected up with no bending of the rear end lines? This should go in the part number section.

Well, OReilys lists it for 83-86 TC. Please move this to the parts section!
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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rsears Offline
Member
#8
Robert - Correct. The new replacement fit the axle tube correctly and also required no modifications to the factory brake line position. Everything bolted in as easily as the factory line removed.
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