I took the Bronco out in a ride a couple of weeks back (my 1990) and on the way home it randomly started pulling to the right. There was a weird screeching sound for a while, finally at 55, it was light the right front brake was hit.

It was a bit scary, but the sound went away and I got it home alright.

Anyways, I drove it one more time and it was pulling to the right really badly.. it's random, not like an alignment issue, and I'm not sure what's causing it.

I decided I needed to rebuild my injectors, ran into shipping problems on parts and it sat for a few weeks, I got all of that back in and remembered that I had that issue with the pulling, so I'm scared to drive it.

Brakes? axle? I know I just payed to have the ball joints and bearings replaced on that side (I know I'm suppose to do both sides at once), maybe 3000 miles ago?

It's a toy and a daily driver.. I abuse the hell out of her (she likes it, i promise) but it's one of the most dependable vehicles I've ever driven, I hate it when stuff goes wrong and I can't immediately put my finger on it.
I don't even see how brakes could cause this, as the issue doesn't start after braking, just randomly while driving. My front axle seems to be in really good shape, ujoints are fine, not that they are even spinning in 2wd. My hubs are new so I doubt they are somehow sticking on.

 

It could be you have a caliper going bad. But unless it pulls to the right like that after you have applied the brakes, the problem is more likely to be a wheel bearing. If it just arbitrarily pulls to the right with no application of the brakes or steering changes, its more likely a bearing issue. Keep in mind too that with the 4WD hubs you have not only inner and outer wheel bearings but spindle bearings as well.

 

But a bearing should make noises at all times, i'm leaning more to a brake failure, get the truck lifted and turn the front wheel, the noise from a bearing or a brake should be easy to tell.

 

Presumably, yes... but when have you ever had a caliper fail by slipping closed. The way he described it, the noise came and went and the pulling did as well while cruising... calipers typically fail by staying stuck closed or failing to close at all. But then I suppose it could have seized after a slight brake application and he drove till it destroyed the pads.

Heck, check everything up there.

 

I had someone known have some issue with her brakes, the caliper was actually free inside the wheel, it would interfere at moments with the movement and at other times it wouldn't even be felt.

But yeah, he'll have to check everything up there to find the cause.

 

I hope this helps as I too had a problem as you have described. I have a 79 bronco ranger xlt and it was pulling bad all by itself feom time to time....after numerous parts replaced ( calipers pads etc ) I STILL had the problem. I then had the lead tech at the local ford dealer drive it and he knew the problem right away. He had me lock it in 4 hi and drive it a while and then unlock it and the pulling was gone! He explained that I had a u joint for the frnt axle shaft binding up and when I locked it in it forced that u joint free and the pulling stopped. I was unsure about his theroy tho and never fixed it only locking it in when the pulling would start untill the u joint started to come apart. I am unsure wether this applies to you because u may have ifs with cv joints but figured id throw it out there! And btw before I went to the dealer I put a new steering box on...what a bummer that was!

 

Check both front brake systems. If the left brake isn't doing it's share of the stopping the vehicle will pull to the right. Had this happen to my Son's 94'. To be safe we replaced both calipers, rotors, pads and torqued everything to spec. Also make sure that when the caliper was put on it wasn't twisted prior to placement which will cause restricted fluid flow to the caliper through the brake hose. This is much more noticable with big tires. You could lose control on an unexpected power stop. Brakes is the one function I will throw parts at. Better safe than sorry.

79Bronco boy does bring up another possibility. Do you have automatic hubs? Those things are known to have problems but I've never heard of them locking and unlocking without torque being applied by the axle. If you do have them even if they aren't the problem you might want to change them out to manual locking hubs. It's an inexpensive change which you'll be happy you did.