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1988 F350
So I started doing the brake pads, noticed one was in backwards... now I need a pads and rotor. Noticed leak in rear drum...ok, rear seals and shoes. Noticed rusted out and missing rear brake lines...No problem!
But, here's the problem, the front of the master cylinder goes direct to front drivers dics with no T. Rear master cylinder port with proportioning valve goes to passenger disc, T's to RABS system then to rear drums. This don't look right to me. I looked online for diagram, nope. Downloaded Haynes repair manual, waste of money. So, What do you think of my fine diagram? Which is correct #1 or #2?
How do you put the pad in backwards and still get the caliper on?
Neither diagram is correct. Master to “T” then splits to front brakes. Other m/c port goes to the RABS hydraulic pump then to the rear axle where is splits to each rear wheel.
I plan to delete the RABS.
#2 is correct then? Front m/c port T's to front brakes and rear m/c port T's to back brakes?
As far as the backwards brake pad. I just bought the truck and drove it home, noticed a slight pull to the right, no grinding. Pulled the tire, it has new pads, must be a sticking caliper, right? Nope just lack of attention to detail. Had to laugh, even though its not funny, its expensive.
You will either have to add an adjustable proportioning valve for the rear or plumb the system like a pre-RABS system. I assume they had a combination valve.
I'll add a combination valve, so should I remove the proportioning valve from the master cylinder?
TooManyMIce - That's what though me off the brake lines look factory or professional installed. This truck is the definition if Easter egg. Should be fun!
In the manual and here in the forum I've read that called a proportioning valve, and a residual valve. How do I verify which it is?
So the plan is to put in a Brake Proportioning Valve with warning light and adjustable Brake Proportioning Valve in the cab.
Will I need a residual valve to stay on the master cylinder, be removed or moved downstream?
That is a residual valve for the drum brakes. The RABS HCU handles the proportioning duties for the rear brakes in that system. Why do you need another brake warning light? There is warning light on the master cylinder.
If the RABS has the factory prop, seems like the easiest solution is to plumb your adjustable prop in its place. You could modify both circuits to let you run an older-style non-adjustable prop instead if you prefer.
Ok that's what Ill do. Remove RABS and add adjustable proportioning valve and not add the non-adjustable proportioning valve.
Thanks guys for the help.
The truck has been in some abusive relationships; work horse, mud truck toy, redneck yard ordainment and now for me a tow rig. The wiring harness is all chopped up, most/all the sensors are disconnected, broken or missing. The speed sensor, RABS system would be easy to swap parts if need be, but the wiring could be a time consuming nightmare, running gear is priority. Most of the brake lines are getting replaced. Now would be the time add an adjustable prop. If I hook up the RABS and can never get the wiring working...
I think in this situation with the condition of the truck the easiest solution is best.
Maybe I thinking all wrong?
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Screwy Brake Lines
Had to laugh, even though its not funny, its expensive.
