Newer brake drum locks up when lug nuts tightened - '78 FJ40 (1 Viewer)

[SteveH]

I have a bone-stock '78 FJ40. I replaced a rear brake drum with a genuine Toyota drum about 10 years ago.
I have owned the truck 28 years and know most of its history.

I just did a brake job with new shoes and 2 new wheel cylinders. I do have the factory paper gaskets installed over the axle flange ends.

This particular 'newer' brake drum, when you tighten the lug nuts (wheels on or off), locks up the hub/wheel. The wheel is locked up pretty solidly, but you can drive away (and it will get hot).

I swapped the brake drums, side-for-side, and the other (old, OEM drum) works fine on both sides. The newer OEM Toyota drum locks up both sides, regardless of shoe adjustment. Any ideas? Both drums appear the same (physically), and have the interlocking 'WW' casting mark. I can see no scrape marks due to rubbing anywhere. I even put indicator paint on likely rubbing areas, and none of it has come off. I also chamfered the brake shoe edges, in case that was it. I'm at a loss.

Thanks - Steve

 

[Jaric00n]

Is it rubbing against the back plate?

like the drum is too deep or something?

 

[SteveH]

I checked EVERYTHING and even spray-painted the inside of this 'new drum' to see if it rubs on the brake return springs or any other part. No clue. Will upload pix soon. Thanks!

 

[SteveH]

I painted the inside of the newer drum with the shiny marks (circled) and can't see any paint scuffing after reinstalling with lug nuts. The other drum is the older, OEM drum from 1978. You would think with a drum that locks up, you'd see a contact point, right?

 

[73FJ40]

Are there any imperfections in the drum surface where it meets the axle flange? Or a smaller diameter hole for one of the studs? Could be cocking the drum..

have you backed off the cylinders star wheels all the way? The new drums likely have a lot more meat than the old ones.

 

[SteveH]

Thanks for your suggestions.

The drum surfaces are flat and true. The drums fit flatly against the axle flange.

And yes - I backed off the shoes on both sides to allow easy drum fitment. I had imagined it could be that a drum was tapered internally, but if the shoes are backed off, that won't be the case. I may go apply some paint-marker paint to the brake shoes (just a dot here and there) and see if there's some odd contact when the drum is slid on.

 

[4x4veteran]

Got shoes in the slots on the brake cylinders?
Look and see if the springs are on properly.
The springs go between the shoe and the backing plate.
A picture of the brake installation with drum off might help.

 

[bigredmachine]

is the drum tight when you put it on before you tighten the lugs

 

[1969FJ]

Are you sure new drum dimensions are exact ? Did you use a caliper to check depth of the drum rim where it goes into the backplate ? There has to be a difference , and precise measuring is required.

 

[raymond2335]

I have experience the same problems in the past. Turns out I didn’t have the shoes correctly seated in the slots on the brake cylinders. The brake shoes werent allowed to sit as deep as they should before I slid the drum over top. Couldn’t figure it out either, all these new parts and when I went to drive away one of the drums were hanging up. It is possible there’s something not quite right about it. More than likely there’s something not quite right about your installation.

 

[SteveH]

The springs go between the shoe and the backing plate.

One spring is front-mounted (always has been). The shoes are 'loose' when I slide the drum on, and only if you press the drum hard against the axle end (or install lug nuts) does it get tight. I have been following other threads and believe I have the adjusters set correctly (the sloped portion of the slot sits correctly against the shoe end). See photos of the left side in this reply.

 

[SteveH]

And the right side:

 

[1969FJ]

Look, if you tighten down the lug nuts and brake system is locking, it makes sense the drum tolerance is to tight and disallowing the designed movement within the design. Where did you get the new drums from , OEM ??

 

[SteveH]

It is an OEM drum from the dealer, ~10 years ago. An earlier reply mentioned that the springs are to go behind the shoes - is that correct (and are mine wrong, then)?

 

[1969FJ]

It is an OEM drum from the dealer, ~10 years ago. An earlier reply mentioned that the springs are to go behind the shoes - is that correct (and are mine wrong, then)?

If I remember right, one was behind and one was in front. I do not believe that is your issue.

 

[Living in the Past]

I would loosen the lugs nut just enough so suing something as a pry bar on the lug nuts to spin the drum so it might possibly leave marks on the location it binding up. That would give a good idea of the issue.

 

[skidplate]

Did you adjust the brake shoes with the wheel off and then mount the wheels? I did that once to make the shoe adjustment easier. Wheel turned smooth until I mounted the tires and torqued the lug nut then they locked up. I mounted the wheels and re-adjusted the brakes and then I was fine.

 

[SteveH]

Did you adjust the brake shoes with the wheel off and then mount the wheels? I did that once to make the shoe adjustment easier. Wheel turned smooth until I mounted the tires and torqued the lug nut then they locked up. I mounted the wheels and re-adjusted the brakes and then I was fine.

Yes - but it locks up on either side, even with the shoes backed off significantly.

I would loosen the lugs nut just enough so suing something as a pry bar on the lug nuts to spin the drum so it might possibly leave marks on the location it binding up. That would give a good idea of the issue.

I will try this - or something like it. There must be a way to 'leave a mark' and find the rubbing location.

Thanks for all the excellent suggestions/observations/questions so far. - Steve

 

[4x4veteran]

Did you adjust the brake shoes with the wheel off and then mount the wheels? I did that once to make the shoe adjustment easier. Wheel turned smooth until I mounted the tires and torqued the lug nut then they locked up. I mounted the wheels and re-adjusted the brakes and then I was fine.

I am leaning toward Skidplate. I can't see anything that is close enough to the axle flange to rub on the drum.
The end of the brake shoe on the last photo looks like it has been rubbed so it possibly is binding when you torque the lugs.
I suggest you run the adjustment down so the brakes are real loose and then try mount the tires and see what happens.

A couple of long shots, check to see if the axle flanges are straight and go to a place that turns brake drums and have them check and see if they are true.(not bent or out of round)

 

[SteveH]

The end of the brake shoe on the last photo looks like it has been rubbed so it possibly is binding when you torque the lugs.
I suggest you run the adjustment down so the brakes are real loose and then try mount the tires and see what happens.

I will try this - making the shoes super-loose and re-fitting. The ends of the shoes are worn (more) because they are brand new shoes with ~10 miles on them.