My front driver’s side wheel is getting very hot when I drive even for 20 minutes or so. Sometimes there is intermittent vibration coming from that part of the car at around 50 - 70 mph. A laser thermometer read about 120˚F on that wheel, the others being about 85˚F. The wheel is too hot to touch for any length of time; the others are just warm.
My mechanic has no idea what the problem could be. He has already replaced the bearing, the brakes, a seized calliper (the whole thing, not just the piston) (we thought this was causing the heat, but it seems to be a symptom), the rotors (warped and not machinable), as well as the U-joint on the passenger side (which seemed to be a source of vibration). He also balanced my wheels and did an alignment. We switched the front wheels to see if the wheel was somehow still causing it, but the left side still heats up even with a different wheel on.
He says it wouldn’t be the transmission because he would have noticed that when he was inspecting it. Maybe a bent hub, but I’d expect that he would have noticed that, and there is only vibration intermittently–not all the time. He doesn’t know what else it could be. Any ideas?
Odometer: 206,000 miles
Check the brake line. They can collapse internally and prevent fluid from exiting the caliper, which freezes the caliper even though the caliper is fine.
BTW, your mechanic should have thought of this. It may be time to consider a new mechanic, especially since it seems he’s just guessing and throwing parts at the problem at your expense.
I agree with @shadowfax Especially on a car this old, the flexible brake hose would have been my FIRST check, the caliper my second, the bearings 3rd. I am surprised the temp was only 35 degrees higher! A brake hose is very cheap and should be changed at this point whenever you change a caliper out.
Yep. plus 3 for the brake line. Gotta be either the bearing, caliper or the brake line not allowing the fluid to go back again after pressing the brake. They probably should have just replaced it along with the caliper since they had to bleed it again anyway. If that’s not it, then must be a problem with the master. He should have replaced the other brake line too while he was at it.
I’d voter for the flex line too, but I’ve also seen badly worn caliper slides cause the caliper to hang up. I’d have him replace the line and inspect the caliper mounting bracket while he is in there getting dirty.
If the above ideas don’t pan out … Did your shop replace the entire caliper, or just the piston? If the latter, ask your shop how much it would cost to replace the entire caliper with a new one. Replace any associated mounting gadgets and hardware too. If the shop hasn’t replaced the pads yet – which would be unusual since the rotors were replaced – replace those.
Why was the wheel bearing replaced? Usually that wouldn’t be replaced unless an inspection showed there to be a problem with it. What did the inspection reveal that caused the shop to replace the wheel bearing? Was it just the bearing replaced, or was the entire hub replaced? That info might be a clue for the experts here.
I talked to my mechanic, and he said the following:
- They replaced the entire calliper, not just the piston.
- He said that when he did the brakes (and yes, he changed out the pads, which were very unevenly worn), the brake fluid came out fine, so he doesn’t think the brake line is collapsed inside–but he did not replace the brake line.
- He suggested that maybe I have a bent hub on that wheel.
My thoughts are that if the hub were bent, I would notice vibration all the time, not just intermittently at certain speeds, and I don’t see why the wheel would get this hot, this fast, if it were a bent hub. You would also think that he’d notice a bent hub when he did the wheel alignment (I’m not a mechanic, but it seems like you’d notice that sort of thing). The rotors in the front were replaced because they were rusted out and warped–he couldn’t machine them enough to make them acceptable. The bearing was replaced because, well, he thought it must be the bearing–in his defence, I did have a bearing go a couple years back on the rear driver’s side.
I forgot to mention that the odo. is 206000 miles on this car.
I will probably try to see if I can replace the brake line myself and see if that makes any difference.
If it is not the line i might suspect the master cylinder, did you check if the right rear wheel is hot too?
He’s missing the point. The lining of a flexible brake line can separate and collapse in a manner that it acts like a “check valve”, allowing the fluid to flow into the caliper when t he pedal is pressed but restricting it from returning up the line (releasing the pressure and allowing the caliper to open) when the pedal is released. And it can do this intermittently.
As others have mentioned, your mechanic should know this stuff. It may be time to start researching a new shop.
Plus 2 for Mountainbike. Its not pushing the fluid into the caliper that is the point, its that it won’t let the fluid go back again and keeps the caliper dragging. New mechanic time in my view if he doesn’t know that. Like I said both should be replaced since it requires bleeding again anyway.
Or here’s a thought, they have ridges along the hose so that you keep the ridges straight all along the hose. Maybe he got the hose twisted when he put the caliper on. Who knows but time for new hoses. And I’m not even a mechanic and my fingernails are clean.
Also could be the bearing is going bad.
I think replacing the rubber hose to the caliper is an excellent next step. If that didn’t fix it, I’d probably replace the hub. The replacement hub probably comes with a new bearing already. It isn’t always so easy to detect a bent hub I expect. You’d think it would show up w/a dial indicator like when measuring for warped rotors, but maybe a bent hub produces weirder effects than that.
(The bearing was replaced already. Only that one wheel is getting hot–all the other three are cool or warm when I check them.)
Nobody thinks it could be a bent hub, then?
I haven’t changed out a brake line before, but I’m up for trying. Does anyone know a good step-by-step online guide? Also, dumb question, but we’re definitely talking about the brake line and not the brake hose to that calliper, right? Or should I just replace both?
Just replace the short rubber hose that links the metal brake line to the caliper. It has to be made of a flexible material like rubber b/c the master cylinder and the metal hoses are all bolted to the chassis, and the wheel and caliper are always on the move, bouncing this way and that, referenced to the chassis. That’s what the suspension system does. The metal hoses won’t collapse. Only the rubber hoses do that. It isn’t that uncommon of thing to happen either, based on the posts about that topic we see here. At 13 years old, definitely a possibility.
And it could be a bent hub. But in the absence of other evidence, less likely than a collapsed hose.
Edit: Let me ask this. If you jack up the car and spin the wheel while standing behind – in line with the wheel – do you notice any wobbling? Try the same thing with the wheel remove, and just watching the hub and the rotor. Any wobbling?
Here’s a fact to consider when considering the hose. The force pushing brake fluid into the caliper is considerable, being the pressure you push the pedal down with multiplied by the mechanical advantage of the master cylinder. The force pushing the fluid back out of the caliper is only that of the rubber ring that pulls the caliper piston back to allow the pad to retract, a small amount of force compared to the force you’ve pushed the pedal with. You might be able to easily force fluid past a collapsed inner liner to apply the brake, but the rubber ring in the caliper might not have enough force to push the fluid back through the hose after the brake is applied, keeping the brake lightly engaged (dragging).
Again, a mechanic that understands how brakes work should know this.
If you were doing your own work, I’d suggest jacking up the wheel, spinning the wheel by hand and noting the amount of force required, then applying the brakes, releasing the brakes, and spinning the wheel by hand again. Do it a few times and see if the wheel continues to drag after the brakes are applied.
It only takes a little fluid pressure to push the pads against the rotor. If you had an old drum brake system you wouldn’t even have a problem unless you wanted to stop the car. The return springs would pull the shoe away from the drum. We must throw another part at the problem; a rubber pressure hose. Without it, you’ll never know.
Yeah yeah, the rubber hose, not the metal brake line unless it is rusted and leaks. The only issue with changing the hose is that sometimes they are pretty hard to get loose, so use a good quality wrench or crow foot. Also careful to not wreck the metal line where the hose connects. Otherwise keep the lines straight, don’t get any dirt in the fittings, and bleed the brakes afterward.
On a 98, if you live in the rust belt you may not get the fitting apart where the rubber hose connects to the steel line. you may have to heat it up.
If that is beyond your capabilities, you should take it to a shop.
I jacked up the front wheels, one side at a time. I was able to spin the passenger side quite easily, but I couldn’t turn the driver’s side (the problem side) at all–is that confirmation that the brake is closed shut? I did this in parked (running) and in neutral (not running), and I could not turn the driver’s side front wheel at all.
I’m starting to think that my calliper was never truly seized in the first place–it was just held shut by a fault brake hose acting as a one-way valve. Sound right?
Well don’t necessarily listen to me but you could confirm it by pulling the wheel off and taking a look at the brake pads and if they are in contact with the rotor or there is a little space. Then you could use a large C clamp to push the caliper piston back a little, just like you would do if you were replacing the brake pads. If you can now easily turn the rotor, you know that’s your problem.