So after my 8 3/4 swap I reused the brake hardware from my 7 1/4.
Both use 10x 1.75 brakes.
The backing plates are NOT the same without modification of the center hole and adding the 5th hole.
All was looking good.
I cleaned up all the parts, bought new shoes and cylinders.
Lubed everything properly and assembled.
Blead the brakes 100 times.
Take it for a test drive.
A little spongy feeling.
Bleed 100 more times.
That feels better.
Take it for a 30 minute test drive and when I get home I can smell hot brakes.
Got the thermal temp gun, right side is 140 deg, left is 100 deg
next morning pull the drum and see obvious signs of glazing.
sand the glazing off and re adjust everything.
pedal still feels ok.
another test drive, 105 left 100 right.
much better
I stopped messing with them.
yesterday another long test drive (to brake in the 8 3/4, 150 more miles to the oil change)
I have the rear hubcaps off so I can thermo the axles lugs and area on the wheel in contact with the drum
1/2 way through I stop and measure the temps, all good 100 ish both sides.
A bunch of stop and go on the way to the house and snif snif, is that hot brakes again?
Get home 140 on the right 100 on the left.
So this morning I pull the right side and sure enough the right primary shoe is stuck off the center post.
Well crap.
I take everything apart and it's not the cylinder, that moves freely, but the shoe is hanging on the outer edge of the backing plate contact patch.
I had kept the old shoes (maybe 20,000 miles and more material than the new shoes) and I compared the two.
The new shoes don't have the large flat surfaces (red new shoe, green old shoe) this allowed the shoe the run over the edge is my guess
If that was not enough.
When I went to put it all back together I was missing the upper center pivot guide
I looked all over for it. It was on in photos I took of the 7 1/4 before I removed the brake hardware. I did not notice if it was on there before taking the hardware off this morning. I checked everywhere, even going through the trash thinking it got cought in a papar towel. Nothing of course and the other brake hardware I have did not have them either. So I reached out to local buddies and thought about driving an hour to the wrecking yards that have some 60s thru 70s A bodies and B, C, E trucks etc.
then I thought, it's not too sophisticated a part, I bet I can fashion one up and in 20 minutes I had a functional replacement while I get a real one.
so far so good took it for a stop and go rest drive and left and right are within 5 deg of each other. I took a few adjustments out of the right side and will test again.
I think the lack of the guide allowed the shoe to get sideways and helped it get hung up on the backing plate.
As long as I can get to the last Mopar show at Bandimere tomorrow, (60 miles one way) I'll be a happy camper.
Both use 10x 1.75 brakes.
The backing plates are NOT the same without modification of the center hole and adding the 5th hole.
All was looking good.
I cleaned up all the parts, bought new shoes and cylinders.
Lubed everything properly and assembled.
Blead the brakes 100 times.
Take it for a test drive.
A little spongy feeling.
Bleed 100 more times.
That feels better.
Take it for a 30 minute test drive and when I get home I can smell hot brakes.
Got the thermal temp gun, right side is 140 deg, left is 100 deg
next morning pull the drum and see obvious signs of glazing.
sand the glazing off and re adjust everything.
pedal still feels ok.
another test drive, 105 left 100 right.
much better
I stopped messing with them.
yesterday another long test drive (to brake in the 8 3/4, 150 more miles to the oil change)
I have the rear hubcaps off so I can thermo the axles lugs and area on the wheel in contact with the drum
1/2 way through I stop and measure the temps, all good 100 ish both sides.
A bunch of stop and go on the way to the house and snif snif, is that hot brakes again?
Get home 140 on the right 100 on the left.
So this morning I pull the right side and sure enough the right primary shoe is stuck off the center post.
Well crap.
I take everything apart and it's not the cylinder, that moves freely, but the shoe is hanging on the outer edge of the backing plate contact patch.
I had kept the old shoes (maybe 20,000 miles and more material than the new shoes) and I compared the two.
The new shoes don't have the large flat surfaces (red new shoe, green old shoe) this allowed the shoe the run over the edge is my guess
If that was not enough.
When I went to put it all back together I was missing the upper center pivot guide
I looked all over for it. It was on in photos I took of the 7 1/4 before I removed the brake hardware. I did not notice if it was on there before taking the hardware off this morning. I checked everywhere, even going through the trash thinking it got cought in a papar towel. Nothing of course and the other brake hardware I have did not have them either. So I reached out to local buddies and thought about driving an hour to the wrecking yards that have some 60s thru 70s A bodies and B, C, E trucks etc.
then I thought, it's not too sophisticated a part, I bet I can fashion one up and in 20 minutes I had a functional replacement while I get a real one.
so far so good took it for a stop and go rest drive and left and right are within 5 deg of each other. I took a few adjustments out of the right side and will test again.
I think the lack of the guide allowed the shoe to get sideways and helped it get hung up on the backing plate.
As long as I can get to the last Mopar show at Bandimere tomorrow, (60 miles one way) I'll be a happy camper.
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