Hey, folks - quick background: Picked up a '78 F250 that sat around for 8 years - brakes work (kinda?) but need some love. The front chamber of the MC was pretty much empty and the rear cylinder was very low.

The pedal is maybe 3 inches from the floor already and is about as hard as a woodpecker's lips. I understand that this is most likely a vacuum problem, but where's the best place to start?

Edit: Maybe the best question is what the order of operations should be.

1) Flush all brake fluid.
2) ???

 

If your 78 F250 is the same as my 79 F350 then the front reservoir is for the rear brakes. If it's empty then you should fill it and then pump the brake pedal and look under the truck for any rear brake line leaks.


You should probably also take your wheels off and inspect the brakes. I believe you have disc brakes on the front of a 78 F250 since mine did. Check out the pads, calipers and the rotor. Check out the brake shoes and wheel cylinders on the rear also. A thorough bleeding of the brakes may also be in order when you are done. Then you will have a solid starting point to go forward from.


Start at the beginning and when you get to the end...stop.


Dennis

 

X2 what he said, insp all and then service/bleed accordingly. If you still are having issues, make sure you are not having a vacuum issue and then new master cylinder and power brake booster (get them assembled) time.

 

This is just my experience but my dent taught me a lesson when going through the brakes. Did the inspection and all looked servicable. Master cylinder was rotten and got changed, wheel cylinders SEEMED ok and discs/drums looked to be seeing pad contact. All bled as expected but still had lock up on the rear under hard braking. Finally set both rear wheels off the ground and found that only the passenger side actually worked in spite of the good outward condition of the wheel cylinders and all corners bleeding as expected. Get the wheel up and turn it while somebody steps on the brakes to confirm function.............that's what mine taught me.

 

If the truck sat unused for 8 years, plan on a new MC, flexible brake hoses, calipers, new wheel cylinders, pads/shoes and brake shoe hardware. Otherwise, one or more of these components are probably going to fail soon after you start using the truck again.

If the MC has leaked brake fluid out of the back end and over into the brake booster, you'll have to replace the booster too. Brake fluid attacks the rubber diaphragm inside and will cause it to rupture.

 

That's good advice! Number one on my list.

This is what I fear. Especially with it not being serviced for so long and being in who knows what shape before that.

Reading my mind. I love having as much original stuff as I can keep, but not at the expense of something like brakes. No leaks from anywhere yet and I've started bleeding the rear. I'm going to price out replacing everything tomorrow. Good advice, thanks.

ALSO... I've pulled the axle shafts and there is practically no lube coming out of there. You couldn't fill a shot glass with the amount of lube that leaked. Cause for concern?

When I pulled the hub bolts, there was a kind of soft rubber material that came out with the bolts. Squishy. Any idea what this is?

I plan on installing new hub seals while I'm back there, but is there anything else I should attend to?

As always, thanks for helping a newbie!

 

I did some reading last night on the axle / differential and am caught up on what I need to do for this project, but I just noticed that the head of one of the hub bolts has been snapped off!



I don't have a welding machine to tack something onto the head and remove it. Any ideas how to back it out?

 

Easy outs, or drill and tap it then jb weld a smaller bolt in the tapped stud.

 

Once its on the bench it will be a lot easier to deal with. Easy out should work.

 

I would see if I could grab it with some vise grips first. Looks like it is sticking out some. If not a left handed drill bit would probably spin it right out. Just make sure you center punch it and drill straight so it doesn't hit the threads.

 

I've had luck cutting a slot in the end with a thin cut off wheel, Dremel or die grinder and then backing it out with a screw driver or one of the drive type impact tools.

 

Thanks! There was a little lip to work with, so I wound up using a hammer and screwdriver to back it out enough to pull it.

 

As for the brakes, I filled the MC and opened the bleeder valve and nothing came out.

I opened it a little more and nothing came out.

I removed the bleeder valve screw and nothing came out.

I'm assuming there's either a blockage in the line or I just need new cylinders. I'm heading to the parts store to get new cylinders, anyway. I can't install them without the socket for the axle, so stay tuned and thanks.

 

If you're gonna buy a new MC, buy one for a '95 explorer workout cruise control. It's aluminum, so it will never rust, and the ports are on the driver side! You will have to buy adapters for the lines because of double flares or something of that nature. Search it on this website and you'll find part numbers for them.

 

Were you expecting something to come out? Not likely.
If the master was empty, then there's nothing for it than you have to actually pump-bleed the brakes. Nothing is just going to come out on it's own. At least not immediately. You might get lucky and gravity-bleeding might work if you leave the bleeders open for an extended period of time.
Even if the reservoirs were full and the lines fully purged of air, you don't always get an immediate flow of fluid out of the cracked bleeder.

Yes, you could very well be correct that everything is buggered from sitting and you not only need new wheel cylinders and a new master, but very possibly a new booster, new soft lines AND new hard lines because rust has had it's way with things down low.
And then, if you're really unlucky, you will also need a new proportioning valve.

With luck it's only one or two of those things, but I would not make any determination on a quick opening of a bleeder screw. I would get a helper and actively bleed it at least the first time to see if that makes the difference. If not, then yep, back to the parts store for more stuff.

Good luck. Sorry if I misread your post and you actually did wait an extended period of time with no joy. Just wanted to make sure.

Paul