Good day All,
I have a second gen 4runner. I think I'm having issues with my brake calipers (Front left). When I go on my first drive of the day, I would have issues with the truck moving forward on its own weight or even with engine power. driving with that issue, it feels like I have a death wobble and the break pedal is hard to compress, but if I do compress the break pedal it pulls to one direction, also the vehicle has power issues. I would have to keep down shifting to gain momentum for the vehicle to move forward.. this is were I get confuse, during the death wobble, the pulling of the vehicle to one direction compressing the break pedal during that time, it would smell like I'm burning the clutch. I'm thinking with the brake calipers sticking its putting strain on the transmission that's the reason I'm smelling burned clutch. during the drive after a while of bearing through the symptoms I have listed, the vehicle loses all symptoms and the driving goes back to normal, I do not have any power issue or any shaking of sorts, but after all that the brakes becomes soft and sponge. I hope I didn't confuse anyone with my explanations. any help will be appreciated. Thanks.

 

From what I can tell, it sounds to me like you have a caliper stuck. It's holding the pads onto the rotor, so as you move, the disc's rotation allows the high spots to press on the pads more and less. Thus, the apparent wobble. This may also be caused by a warped disc, especially in conjunction with a stuck caliper.
You may have a partially collapsed flexible brake line holding pressure on the caliper, but I suspect that it's the caliper itself getting stuck.
Could also be a problem with the master cylinder, not completely releasing the pressure on the front brakes. Make sure the pedal alignment is correct.
When did you last bleed out the brakes? When you get the wobble, hard pedal, and burning smell, have you tried opening the bleeder valve on the side it pulls toward? If you do, does it stop the hard pedal, etc?
What color is the brake fluid? This is a follow up to "when did you last bleed out the brakes?" Brake fluid absorbs water from the air over time, and it does some odd things when that happens. If it's been more than a couple years, You may have bad fluid in the system. Bleed each caliper, starting passenger rear, drivers rear, passenger front, driver front, LSPV. Bleed each one out until new, clean, fluid comes out. Make certain you don't let the fluid in the MC get too low. If it does, it can suck air into the MC, and then you have to take it off and bench bleed it to get the air out.

Most likely though, it's a stuck caliper. They're known to do that, and it's easiest to just replace it. There are rebuild kits for them, but given the cost of the rebuild kit, and the time it takes to do the rebuild, it's just as easy to get a new one. You may well have a warped disc, too. Do a run-out test on it. Only takes a moment, and can tell you very important info.

Pat☺