Rolling resistance question... (1 Viewer)

[MrMoMo]

Hey guys, diving into my "new to me" 1993 80 and on the list was adjust the parking brake. Found the procedure, simple enough. Popped the rear wheels off. How hard should the discs be to rotate by hand? (Yes the truck is in neutral, no I don't have a locker in the axle)

Parking brake handle goes all the way up. I adjusted the cog wheels inside the drums until I couldn't turn them more (shoes tight) then backed them off a hare until I had some motion in the drums. Parking brake now goes up half of what it did before.

Great.

I have to use a pry bar in fear of snapping my screwdriver when trying to rotate the discs. (Placed between wheel studs). I backed the cogs off even more, but it makes no difference. With the wheels on, I can turn by hand, but it's a lot more resistance than I would expect, to the point where the input shaft sometimes turns... This to me says drag at the wheel...

How hard are these things to rotate normally? This is not my first brake adjust, but it is the first time working on the back end of the 80.

I had just put 2000 miles on the truck, got about 14.5mph (highway) I checked the wheel and hub temps frequently during the drive and didn't notice excessive heat.

Could it be that one of my calipers just seized, or partially seized? What else should I check?

 

[86tuning]

That's the way they are, mostly. You should be able to rotate the tire by hand. A sticky brake will obviously make it worse, as you're suspecting. Trucks are big and there's lots of friction, a lot more in a Landcruiser than your garden variety civic with manual trans.

Caliper service is always a good idea when the rims are off. Simply open a bleeder valve and retract the caliper simultaneously. I apply vacuum with my vacuum bleeder but any bit of hose into a bottle will work fine.

I am lazy (read: a highly efficient professional) and use a large pry bar to do it without removing anything else. I actually usually do this with the wheels still on the car, but up on a hoist of course. Once a year or every 20k miles (32000 KM).

If you can't figure out how to do that, unbolt the two 14mm bolts to remove the caliper from the bracket and squeeze the piston back in with large waterpump (20" channel-lock) pliers. Do so with the bleeder open so that you can remove old grungy fluid.

Then reassemble and re-inspect. Bleed the caliper if you have a helper handy. Top up with fresh brake fluid.

 

[86tuning]

Oh, when we adjust park brake or drum brake shoes they're typically tightened til the wheel stops turning, then back off three notches or so. It's okay to hear the brakes touching, but you shouldn't feel them.

On a disc brake/drum setup like we have on the full float axles, removing the caliper first helps so you KNOW that they're taken out of the equation.

 

[Howard705]

And you will also be turning the other wheel the other direction through the differential-so you feel that drag too

 

[scrowley]

Simple rule of thumb is give the tire a good spin and it should make one full rotation with the proper drag from brake shoes. Has worked well for me in the past.

 

[MrMoMo]

Simple rule of thumb is give the tire a good spin and it should make one full rotation with the proper drag from brake shoes. Has worked well for me in the past.

Yeah, that's sort of in line with what I would expect... The way it is right now there ain't no way in hell it would even make a quarter rotation! I think I need to pop the callipers off, and maybe even the rotors... Clean everything up and get a good look in there. Something just doesn't seem right.

 

[MrMoMo]

Pulled the calipers off and everything spins nice and free now (as free as I would expect) Pads and shoes are pretty much at the "replace me" time so I guess it's all good.

 

[gunnerB]

Pulled the calipers off and everything spins nice and free now (as free as I would expect) Pads and shoes are pretty much at the "replace me" time so I guess it's all good.

Wait so you once you pulled everything apart and cleaned it up, once put back together, you had a ton less resistance and everything is in working order? Only asking because I have my tears wheels off right now inspecting due to vibration and a little wheel hop as of late..definitely not a fun ride right now