Sudden dangerous braking pull.
 

So my buddy and I were coming home after dropping off a bridgeport mill with a JLG drop deck trailer. Towed out there just dandy but coming back she generated a dangerous pull to the left (lane switching variety).

A little back story is I recently did rotors, pads and repacked the bearings. I also bleed out the rear and adjusted the drums and had a lovely firm pedal.

So i get her home, drop the trailer and head to the parts store. I figure the calipers or brake hoses are causing the issue. Replaced those, bleed, bleed, bleed. Take her out for a spin (still a lovely firm pedal) and the **** thing still likes to switch lanes with the brake pedal. Left rotor feels warmer than the right so I am assuming it is still in the brake system. I did not replace the center or hard lines FYI.

Im at a loss since it just came out of the blue. No lead up or nothing, just BAMN, welcome to the next lane to the left...

Any Suggestions? This is also a stock 1992 w250, not my old green one.

Do you have a laser temp gun or what ever you call those things? I find them handy to isolate the hot spots or at least see if it is the hub or the rotor etc. But since it happens only at braking I should think it is somewhere in that system and not bearings etc.

Hard line not pinched or bent? Does it correct itself when you let your foot off the pedal or does it still pull? Something on the disc that is making it grab?

Check the steering gear mounting plate for cracks. Loose suspension parts too.

She goes back straight after letting off the pedal. I question the hard line but its strange that it just randomly started. Ive had plenty of cracked steering plates, definitely not it (and I inspected).

rear axle leaking oil/contaminated lining?

I’ll look but it’s a pull that yanks the steering wheel. Thoughts on a king pin bushing? The one in there is split.

front brake not installed properly[duhhh]

Same issue before and after caliper replacement. Also this started out of the blue...

Grooved or split ?

New, they have grooves on them, but split (meaning broken) is not a good thing. Quick and easy fix, though.

I sure wish I had a 4x4 with all that extra stuff to maintain. [laugh]

Drivers side bushing was split as it should be but worn and deformed...Also not the problem. Replaced both as they were cheap and figure it would not hurt.

Replaced the passenger hardline with some creative bending, finally using the flaring tool from the bottom of the junk drawer. Bled, chased a leak and drove down the road. Step on the breaks and the **** thing pulled again, though not quite as violent. A little grumpy I tear through the neighborhood gassing and braking hard. Notice the pull diminishing. Keep doing it down a couple of grades and boom, started stoping straight and hard. I will say the brakes got rather toasty during the process but something happened for sure. Brakes are frighteningly strong now. Open to speculation, possibly poor quality brake pads seating? No clue but I'm going to put a couple miles on her tomorrow and drop off the trailer, bleed it one more time and then call it good... What a way to ruin a nice weekend.

Check the front U joints. I had the same thing happen

You mean the axle u-joint?

I'm sure he meant that, yes.

One of my front axle joints froze up on one axis, and whenever I made a turn, the truck refused to return to a straight driving direction. Hubs locked or,not

Not sure if the axle joint being bad would cause a hard pull, as its not being tweaked driving straight.

Yes I meant the Axel U-joints. Just like NJTman stated the joint would seize up when turning and pull to the side and scare the crap out of you.