86 F350 1 ton Brake bleed procedure

[Pizzadude]

I have a thread going in the project area but wanted to post this here.

I've read the procedure for bleeding this truck as follows.

Push the proportion valve pin (IN) and bleed fronts as normal. Can someone confirm this please.

Also after bleeding the fronts I'm assuming I release the valve and do the rears?

Thank you.

[Pizzadude]

Ok no button on this one.



What the heck is this thing on the rear end? Is it something I need to deal with for the bleeding?


Thank you
I can take more pix if necessary.

[85lebaront2]

Piece on the rear axle is a load compensating valve, no adjustment unless it is replaced. Pin referenced should be on one end of the valve/failure switch on the front frame in your bottom picture.

Piece of advice, in the rear where the brake line makes the turn from lengthwise on the frame to go over to the load compensating valve, that is a low area, examine the line there for rust. I blew one out towing my 5th wheel, lost rear and trailer brakes (nice old fashioned Kelsey-Hayes hydraulic actuator).

[Gary Lewis]

The factory shop manual section called General Brake Service is on that tab at Documentation/Brakes.  And in it you'll find this:

Centralizing the Pressure Differential Valve
After repairing and bleeding the primary (front brake)
or secondary (rear brake) system, the dual-brake
warning lamp will usually remain lit because the pressure
differential metering and proportioning valve is in an off
center position.
Centralize the pressure differential metering and
proportioning valve as follows:
1. Turn the ignition switch to the ACC or ON position.
2. Make sure that the master cylinder reservoirs are
filled to within 6.35mm (1/4 inch) of the top with the
specified brake fluid.
3. Push the brake pedal down, and the piston will
center itself causing the brake warning light to go
off.
4. Turn the ignition switch to the OFF position.
5. Before test-driving the vehicle, check brake
operation and be sure the pedal is firm.

[Pizzadude]

Thank you Gary I found it just a little bit ago and all is well now.

Lots of info in that area.

[Pizzadude]

Thanks Bill i did the ignition reset thing and it worked.

I did not find a pin other than the one inside the sensor assembly. Is that what you meant?

I got them all bled and they are good.

[ArdWrknTrk]

The 150 & Bronco have a different combination valve than the bigger 250 and 350 brethren.
There is a plunger to depress or pull out (depending)
But, if a firm stab of the pedal has put your light out then the shuttle has re-centered, and whichever system lost pressure is now open again.