Replaced one rear rotor - getting a lot of heat now. (1 Viewer)

[MomoSmoothie]

Okay so TDLR version: I changed out my left rear rotor as the original was chewed up due to PO neglecting the brake pads & the caliper piston was full on metal-on-metal. The right side rotor seems fine, no grooves no damage, the pads never wore through. So I only opted to change the one side. I have heard this is not preferred because it can cause uneven braking, but i've also heard people say that it is fine, that the pads will eventually wear in and seat where they should be on both sides and its no problem.
My 80 is a HDJ81 with those stupid expensive one-of-a-kind rear rotors that are like $300 a pop, so I really didn't want to have to shell out $$ for both sides if i didnt have to.

Yesterday I went for a drive (about 400 km, out of town and back) and i noticed my wheel with the new rotor was considerably hotter than the rest. Is this normal for a new rotor? I know its can't be the caliper seizing because I replaced that part last fall. *edit: should point out that there was no burning brake smell that i could detect either*
The thickness of the new rotor is a few mm more than the one i replaced, presumably due to the old one having a bunch of material worn down from it. I put new pads on both sides in the rear when I changed rotor.

The other confounding factor is this:
I tried to do this job earlier last year, and while trying to get the rotor off I didn't realize I had to back off the ebrake so I accidentally mangled some stuff in the ebrake mechanism. I had a couple of springs come loose and were just tumbling around in there. I then realized i should probably order new pads before changing the rotor so I just slapped everything back together as it was, deciding that I didnt need a functional ebrake for the time being anyway.
This time when i successfully pulled the rotor, I found the 2 loose springs - i do not know what they're called - but they held the 2 sides of the brake shoes (i guess?) in place via a small pin and 2 spring plates. {see photo attached}. unfortunately one of the pins had fallen out and is gone. So i only reassembled the one side, thinking that it would be fine considering i've been driving for months with the ebrake not in working order anyway. Now I'm wondering if only having one spring in place is causing the parking brake to drag unevenly on the rotor, causing the heat?

When taking moderate speed (30-50km) right hand turns, I hear an oscillating scraping sound coming from my rear left wheel. It doesn't happen when braking normally. I do not believe it matters if im pressing the brake or not while in the right hand turn. I'm wondering if this sound is coming from the parking brake? The parking brake is pretty weak currently, it only engages when pulled all the way to the end. and I tried driving in a straight line with the ebrake engaged and it doesnt make this noise. So im wondering if this noise and the heat are 2 different issues.

Sorry for the long winded post, i hope it isn't confusing. Mainly im just wondering if i need to shell out $$ for another rear rotor on the right side, or if there are some other considerations im not aware of. Im going on a road trip at the end of next week and i don't wanna be overheating my rotor and cooking my wheel bearings.. currently my last resort is just to put the old grooved rotor and the old pads back on

 

[Michael Hanson]

Hi, Sounds like a caliper is stuck. How old are they? Have you checked both? Mike

 

[MomoSmoothie]

The right rear caliper was replaced Oct 2019, i will remove it tomorrow and check but I doubt that it would have seized up so quickly - i only have about 13,000 km on it.

 

[AndrewInf]

I would double check that the banjo bolt isn't rubbing up against the piston inside the caliper. I had this happen with a set of NAPA calipers earlier this year, they gave me replacement banjo bolts that were way too long. When torqued down the end was pushing just hard enough on the brake piston to make the pad drag because it simulated slight brake pressure at that corner and I was seeing rotor temps over 250-300+F and horrible brake pad smell.

 

[jonheld]

Let's get the nomenclature correct first.
You have rear drum brakes.
You replaced a drum, not a rotor. You don't have calipers, you have wheel cylinders. You don't have brake pads, you have brake shoes. You do not have banjo bolts and soft lines to the wheel cylinders. You have hard lines plumbed directly off the axle.

The parts you have circled in red are to keep the individual shoes against the backing plate. Without those in place (there is 1 set per shoe) the springs attached to the shoes will pull them off the backing plate and the shoes will not seat correctly inside the drum.

The automatic adjuster (part #52 in your diagram) works with the hand brake mechanism to keep the shoes in proper adjustment. If you don't use the hand brake, the shoes won't adjust correctly and your rear brakes won't be as effective. You will have more pedal travel as well.

The part number for the rear drum should be 42431-60150 and can be had for under $130.

 

[Squash]

HDJ81
You must have a rotor with internal park brakes.
The problem is most likely a seized caliper, this happens because crud builds up around the piston as your pads wear exposing more of the piston. When new pads are installed the piston is forced deeper into the housing trying to clear the ring of crud.
Options are new caliper or a combination of cleaning the old system and or rebuild.
To save some cash remove the caliper and insert some wood where the pads live. press the brake pedal and check the exposed piston.
If you're careful you can move the rubber boot in order to clean out the rust and apply some lube.
Before reinstalling I would cycle the brakes a number of times before buttoning her up to ensure smooth operation.

Be sure to lube the pins and internals as your calipers/pads also track side to side.

 

[jonheld]

HDJ81
You must have a rotor with internal park brakes.

His parts diagram clearly shows a wheel cylinder.

 

[MomoSmoothie]

Let's get the nomenclature correct first.
You have rear drum brakes.
You replaced a drum, not a rotor. You don't have calipers, you have wheel cylinders. You don't have brake pads, you have brake shoes. You do not have banjo bolts and soft lines to the wheel cylinders. You have hard lines plumbed directly off the axle.

The parts you have circled in red are to keep the individual shoes against the backing plate. Without those in place (there is 1 set per shoe) the springs attached to the shoes will pull them off the backing plate and the shoes will not seat correctly inside the drum.

The automatic adjuster (part #52 in your diagram) works with the hand brake mechanism to keep the shoes in proper adjustment. If you don't use the hand brake, the shoes won't adjust correctly and your rear brakes won't be as effective. You will have more pedal travel as well.

The part number for the rear drum should be 42431-60150 and can be had for under $130.

No sir you are incorrect, and perhaps it was my mistake to include the parts diagram that I did - i was just trying to find the illustration of the internal parking brake shoe mechanism, in order to get some input on whether improper reassembly of the parking brake could be a cause of the overheating.
This is a more accurate diagram , upon doing some more digging:

I have disc brakes in the rear. Its an HDJ81, meaning from Japan; they came with rear discs while the US model had drums til the later years.

In any even it seems like most are pointing to the caliper as the culprit; weather's finally cooperating today so i will pull it apart and investigate.

 

[jonheld]

Well the concept of the shoes is the same. If the parts holding the shoes in place are missing, then the shoes will not seat properly in the drum.
Certainly inspect the caliper, but replace the missing parts.

 

[Squash]

You can remove the park brakes for now.
Isolate the systems.
Betting caliper.

 

[MomoSmoothie]

Upon a second look and a closer inspection is does indeed appear that the caliper is not moving as freely as it ought to be.. I went ahead and got 2 new rear calipers, took out all the parking brake hardware for good measure.
I think, however, either me or my LC are cursed. I have yet to do a single job, big or small, that goes smoothly and as per the user manual every time.. just as I'm bleeding my brakes after having reassembled all the new shiny bits, i discover a leak from the banjo fitting on the caliper.. 4 different washers later, leak still persists. it seems like either the fitting itself or the caliper surface are the issue.... back we go to pick up a new caliper and probably a new line for good measure..

 

[Squash]

Good Luck!
When you finally repair the park brake be sure to adjust them snugly otherwise they suck.
Pay attention to the star wheel adjuster, be sure to lube moving parts inside and outside.
When doing the park brake you will adjust till you cannot spin the wheel by hand, but can with the tire on, but not fastened. I use a flat screw driver to adjust the star wheel. Be sure to put the rubber plugs back and add a little grease to the two disc removal threads between hub and lug nut holes.
BTW Plan on upgrading to 16" rotors next time you do the fronts, don't forget the bigger pads as well.