88' F350 front brake issue

[clayhwalker]

1988 F350 crew cab longbed 4x4
12v Cummins swapped
35" tires no lift

I am having brake issues and I'm not sure how to proceed. Here is a rundown of the issue and steps I have taken.

Truck started to pull to the right when braking and started to smell smoke so I pulled over and the LEFT side brake pads were burning (actual flames). I got the fire out and cracked the bleeder and fluid shot out like crazy. Obviously it was locked up.

Pulled and replaced both calipers and rubber lines. Pads were almost new so I reused them. Took it out for a drive and it still pulls to the right. I thought maybe the pads were messed up from over heating so i hit them with some sand paper to remove any glazing and put the driver side pads on the passenger side and the passenger side on the driver side. Another test drive and I am still pulling to the right. I am at a loss on what to do next. I have upgraded to a hydroboost system with all new parts about 10k miles ago. Also, I noticed my Drivers side shock is blown (New ones ordered) but I don't think that would make it pull to the right.

Any advice is greatly appreciated since I don't know where to go from here.

 

[8769bigred]

Sounds like you have eliminated some of the normal brake issues. I’m not familiar with the hydro boost system so I don’t know what could wrong there.

I would maybe stick a dial indicator on the rotor and check for run out. This would verify you don’t have any problems with the spindle and or rotor. Also check the relationship between the caliper mounting bracket and the rotor. I had a bent caliper bracket on a Dana 60 that caused some brake issues but not as drastic as yours.

 

[u2slow]

These calipers are famous for a piston sticking, and/or the caliper not staying straight in the guide slots because they are worn. New calipers should be better than remans.

 

[ROCK HARVEY]

What pushrod did you use between your hydroboost and your brake master cylinder? Is there any chance it’s slightly too long? I’ve seen intermittent lock-up issues before with an adjustable pushrod that was not adjusted right.

Am I understanding right that the truck only pulls to the right when you’re braking? Does it by chance pull to the left when you accelerate hard? If so it might be suspension-related, but that seems unlikely if it showed up suddenly alongside the burning brakes.

 

[franklin2]

The hydroboost and the master cylinder are common to all the brakes on the truck. So I would think that would not be the problem.

I would drive it some and then stop and feel both front wheels, see if the left is hotter than the right. If it is you still have the same problem.

You did replace the rubber caliper mount pins? Where they go is all clean and lubricated with high temp grease or never seize?

Did both of them bleed the same when you put the new calipers in place?

 

[clayhwalker]

They both bleed the same. I didn't lubricate the caliper mounting pins since they don't move. Am I missing something on how the pins work?

 

[mf7lakes]

Um, Rubber caliper mount pins????

Mine are metal -- or at least I thought so

 

[clayhwalker]

They are metal on the outside but rubber on the inside.

 

[ihc1470]

The pins do not move but the caliper moves on the pins. The suggestion of feeling the brakes after driving for a while is good. You could also use on of those point and shoot thermometers as it will give an acurate temp reading on both sides. The other suggestion would be to apply the brakes a few times and see if one side is holding more pressure than the other. I would test one side and then apply brakes a few times before test the other side. Both sides should be equal so releasing pressure on one side should also bleed pressure on the other. There should be very little pressure if things are correct. The other issue I have run into years past was the pistons in the master cylinder would not return far enough to uncover the compensating ports. It was asked above if you have check push rod length during the install. Have you?

 

[clayhwalker]

I don't remember what the push rod length was, I did the upgrade a couple years ago. It has been working fine for thousands of mile so I am thinking that isn't the problem.

 

[clayhwalker]

OK, I pulled the calipers and lubed everything accordingly. Test drove and still pulling to the right. I am at a complete loss.
Could the blown shock make it pull like that? I am at a complete loss on what to check next.

 

[DirtyWood]

Since you had severe overheating of the left/driver brake pads I wonder if the rotor is now heavily glazed and the pads can't grab on to it properly. Just a guess.