Having a Brake issue with an 85 E-150

Haven't gotten too far on FTE regarding this issue so I thought I would try my luck here .

This problem started a few weeks ago where the brakes started getting spongy and the pedal would go almost to the floor, the Van would still stop but it just took longer. I bled the system that fixed it for a little while then the problem reoccurred this time resulting in the lovely Red Brake Light coming on which was not a sight I wanted to see driving down the road at 40 mph with my Mom and Handicapped Brother on board.

The truck would still stop but I had basically lost pressure to the back brakes so we were basically relying on the Front discs to stop. I would imagine doing this for prolonged time could warp the discs because of the added heat. Bled the system again and once again the problem went away but came back in less then 24 hours this time the Brake Light would go on and off intermittently pumping the brakes would usually make it go out.

The other day I replaced the Master Cylinder and flushed and bled the lines with new fluid this time I used Valvoline DOT 3 instead of the Prestone Synthetic DOT 3 I had in there previously (probably not much difference since all Brake Fluid is essentially Synthetic or so i've been told).

The problem still has not gone away completely the Van seems ok for short trips but I wouldn't trust driving it very far, as the pedal still seems mushy at times and goes alot furthur towards the floor then I would like. The Brake Light still comes on at times though not as often as it was coming on previously so replacing the MC helped some but it didn't fix the problem. entirely. This is really perplexing and i'm hoping someone here can shed some light on this problem. It seems like air keeps getting into the system somehow and I can't figure out how.

Now for the Tech Specs (Sorry to make this such a long post).

Year: 1985
Engine: 302 (Not that it really matters)
Trans: Auto (Again doesn't really matter)
Has Power Brakes (I'm used to my Maverick which is manual)
Does Not have ABS (Thankfully)

Also I replaced the Wheel Cylinders in back a year or two ago I checked them recently they don't appear to be leaking, the parts guy at Kragen mentioned they might be the problem but I don't see how, the lines also appear to be fine, no leaks anywhere, though I do notice fluid on the sides of the MC and the lines below it but this happens only after driving the Van not from just sitting in it and pumping the brakes so it's like the MC keeps overflowing some (I hate the old Ford Master Cylinder design with the lock bar cap, I would change to the new plastic reservoir design but i'd have to change more then just the MC and I don't need that hassle).

 

Possible rear out of adjustment... Does it pull when braking?

 

brake booster, my 86 f150 did that before i sold it

just became spongy slowly over time, i replaced wheel cylinders cause i had one leaking anyway, new master cylinder and still did it

does it make an air blowing noise from around the brake pedal?

 

Now that you mention it I think it does sort of I always dismissed it as the vacuum though, that would also explain why the pedal doesn't go to the floor without the booster but I always thought these things never failed just the check valves, I'll check it though thanx..

No no pull I did have to replace the self adjuster on the right rear side but that was a job I should have done a long time ago when I replaced both sets of brakes back there. I changed the adjuster on the other side and at the time the right one seemed ok, I dropped the ball on that one .

 

I asked about the pull cause I once had a caliper hose that was blocked that caused all kinds of issues. The light tends to make me feel that it is hydralic related rather than booster. I still say adjustment... hopefuly nothing has come apart in the rear.

 

Power booster or bad M/C.Only other possibility would be a bad proportioning valve thats leaking internally or a bad residual pressure valve which your truck shouldnt have unless its 4 wheel disc and or ABS equipped which it isnt.Good luck.

 

Well I haven't tested the booster yet will do that a.s.a.p. but I'm still focused on hydraulic too because of the light. I did flush the lines real good to make sure they weren't clogged the fluid runs from the WC Bleeder fittings clear and clean. I might replace that rear hose for the hell of it but from what I can tell it looks good God knows how old it is though.

I really hope it's not the proportioning valve because I cannot find them anywhere at any of the Auto Parts stores around here. It comes up unavailable in their computers. I highly doubt the dealer would have them either because they only seem to carry parts for the newer Ford's that they're used to servicing daily. I was told by one parts guy that they don't usually fail because there is no diaphragm in them, but I don't know I know they can clog though. The Haynes Manual says they aren't serviceable so I have no way to take it apart and look for myself but I know Haynes has been wrong before so never know :16suspect.

Never seen an E-150 with all disc but I wish this one had it, only thing drums are good for is the parking brake.

 

A bad booster should give you a high, hard pedal not a low spongy one. I agree with Blugene on the rear adjustment. This will cause the conditions you describe. But are you also saying you're NOT getting fluid to the rear? If not start at the master and work your way through the system untill you lose fluid.

 

Make sure the pistons in those wheel cyls' are not frozen in place or sticking.A bad brake hose can also cause the problem you describe.They get soft and will balloon when you step on the brake.This is very dangerous as it is only a matter of time before the hose pops.Also make sure your calipers are sliding back and forth on their mounts,this will also give you a funky peadal if they are sticking or not moving at all.This is often accompanied by hot brakes and or pulling to one side depending on how and where they are frozen.

 

All good info. I like the one about the wheel cylinders being frozen. Just cause you get fluid don't mean it aint frozen.
The rear drums are good for brakes too... they have to be adjusted right to get good performance. If they are way out, the proportion will be affected = spongy and light.

 

Hmm guess I will just go ahead and replace that hose, from the sound of that it sure couldn't hurt even if it doesn't fully resolve the problem, I do know it's an old hose to my knowledge it hasn't been changed in a long time.

The last time the brakes were done by somebody other then me was Sears Automotive back in 03 they put on new drums after they changed pads on front and shoes on back (they did a lousy job of it too). Don't recall them replacing any brake hoses I do know they did not do the front I did those back in 04 because I noticed the left front one had a balloon spot on it and just changed em both.

I'm pretty sure the calipers are fine, I'll try and check them if I can get my friend over to pump the brakes while I watch the calipers. There is no pulling from the front though and after the problem first started I put it up on four jack stands put my heavy toolbox on the brake pedal (still had some vacuum boost), was able to spin the back tires albeit with very little resistance the front tires however would not budge.

I can check the WC's when I replace that hose if one of them is frozen I suspect it's the left rear one because thats the wheel I had trouble bleeding (could not seem to get the air out took forever). They are Brakeware Wheel Cylinders bought at AutoZone about two years ago so shouldn't be bad normally I get quite a bit of miles out of a WC this would be a first. The Mav also has Brakeware WC's so far they haven't been a problem though that car has maybe been driven 10 miles in four years .

Today I drove it around for a bit Brake Light stayed off but the pedal is still very spongy. Disabled the booster and drove it around the block very slowly to test a theory could hardly stop, with booster stops ok but as I said still spongy pedal. I backed it up several times and hit brakes to self adjust the drums back there pedal didn't firm up any but since I replaced the Self Adjuster on the right rear it does stop a little better.

Thanks for the info everyone.. appreciate it .

 

Don't rely on the "self adjusting". The resistance you feel on the rear could be the drive train... just a thought.
Is there a access hole at the bottom of the backing plate? Sometimes they are not punched out from factory. If you see two punches, punch out the one that is lined up with the adjuster. Obviously you might want to visualy inspect the brakes THEN proceed to adjust them to a slight drag. Take note of the e brake. Is it low? Correctly adjusted, it should be high and firm.

 

Yes there is an access hole there, when I replaced the self adjuster I put a new protective rubber cover that came with the Self Adjuster Kit in there along with a new actuator cable, Springs were replaced when I did the brakes because I needed a new clip for the Parking Brake Lever (had to break the old one to get it off) and they only sold them with the Spring Kits. I figured new springs couldn't hurt right.

The E-Brake is strong and does stop the van if needed, I tested it driving around the block and I was able to stop in a few seconds with just slowly applying the E-Brake. I don't make a habit of doing that because I don't want to overheat the drums.

 

LOL! Altho we call it an "e brake", I don't know anyone who has thought to use it fast enough. It is really (in my opinion) for securing the vehicle when parked, I guess. I once had a Corolla, those have a levar. The levar is much better in a panic stop...keep us posted .

 

That E-brake lever is great for brake turns too