2.75 to 3.50 3rd member swop issues

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tfowler9

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1971 Spring Addition Coupe
(dressed up as Mach 1) full gauges,
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oh brother!
Here we go!!!
So
After I did the 3rd member swop( 2.75 to 3.50) I have had a back brake issue. First I could smell brakes after short ride. I adjusted the new brakes. Spun the wheels and tires spun freely. Nice!

Went for another rid. No more smell of brakes. But after the ride I checked the temp of the back and front brakes. Front were under 100 degrees but the back brakes were both around 245 degrees. You could smell what seem to smell like if there was plastic stuck to something hot. I had new bearings and seals for the 28 spline axles.
I’m worried that I’m getting gear oil passing past the seals and into the brake drums!
Don’t have time right now to pull the wheels off and look into the drums.
Is there a way without pulling it apart to put inspect the back brake issue
I would check your axle seals . Didi you replace when you did the swap? If there are torn they can leak into the brakes.
 

Superbond

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I changed everything. Bearings, axle seals and brakes. I haven’t had time yet but I want to take her out for a run and check the temp at the brakes and the pumpkin. If there the same temp. I’m thinking there is an issue with the new 3rd member I bought. If only at the brakes (which I’m hoping) then it’s an easy fix
 

Superbond

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Yes I did use the self adjust on the correct sides.
I went for a 10-12 mile run, mostly highway. When I got home I checked the temp at the back brakes and differential.
Brakes around 120-145. Differential was 110.
That sounds normal. No?
Maybe I should have took her for a longer ride to see what the temperature reads
 
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Yes I did use the self adjust on the correct sides.
I went for a 10-12 mile run, mostly highway. When I got home I checked the temp at the back brakes and differential.
Brakes around 120-145. Differential was 110.
That sounds normal. No?
Maybe I should have took her for a longer ride to see what the temperature reads
That sounds normal to me.
 

Superbond

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That’s what I think.
I will take her out for a longer ride soon and will let you all know what the temp is then.
Can’t see it just fixing itself. But wouldn’t that be nice!😊
 

Superbond

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Took her for a run yesterday. Drivers side was 445 degrees at the drum! Passengers side was 158 @ the backing plate( I should have checked @ the drum) the differential was 145 degrees.
 

Superbond

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So
I took off the brake drums and there was a lot of brake dust. Also melt burnt. It was a mess because when it was over 400 degrees I took the liberty to cool it down with the garden hose! A hole lot of steam came from them. I wanted to cook them down fast so no to damage the axle seal and or bearings ( which are new). I took the air hose and brake clean to clean it all up.
Everything looks fine! Don’t get it!
To remove the drum. There was no tension. They come off and go back on easily.
I did both sides like that (both side looked the same). I put the drums on and a couple wheel nuts and started the car and ran it( on jack stands). Got to speed up to 70 mph for few minutes. Then without using the brakes it shut down the car and took off the drums to see if any differential fluid was leaking into the drum.
Nothing!
Did it again but this time I put the brakes on a number of times and you can hear them working as they should.
Took off the drums both sides and it all looks great!
Do get it!
Ever time I go for a drive longer the 15-20 minutes the brakes heat up to insane temps. More the driver’s side but still 445 degrees that crazy!
The only thing I couldn’t do on jack stands is simulate turning that would send differential fluid down the axle shafts towards the brakes.
 

Superbond

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FOUND IT!!!
Took the drums off and there is was! Gear oil coming from the axles. Both sides! I know it had to be that!
So I was thinking to myself. Why would that happen and why both sides? Then it hit me! They must have given me axle seals for a 31 spline axle. That would make sense! No?
I call Napa and they looked up what I purchased. It said the seals were for 28 spline axles. But that had to order them from their warehouse. Doesn’t mean someone didn’t ship Napa the wrong seals. I know they didn’t look at the parts I picked up to make sure they were the correct part number. So I order more from Napa and order two from fat guys. They’ll all be in tomorrow. I will compare them and install a pair.
If that wasn’t the issue why else would the axles leak?
 

Superbond

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I took the axles out and pulled the seals. They are the correct seals which is confusing. How is the oil getting past the seal?
I’m I supposed to use silicone behind the seal? Did I set the seal in to far. I see the axle is thicker at the seal then quickly reduces.
 

Superbond

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When I took the new seals out they were fine except from where I prided on them. I just installed the new seal and made sure I had them lubed good and never rested the axle on them when inserting them.
It could be a little over filled with gear oil. Would that do all this?
 

Superbond

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I put grease on the inside to help the spring from moving. Then gear oil around the rubber of the seal
 

Sheriff41

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I put grease on the inside to help the spring from moving. Then gear oil around the rubber of the seal
That's fine. If you overfilled the gear oil "a little"; yes, that could cause your issue. Remove the fill plug in the differential housing and allow any oil that runs out to drain. Once it stops, replace the plug.
 

JJU9507

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POSSIBLE ISSUES
1. sticking wheel cylinder
2. backing plate contact pads worn/grooved, preventing return
3.If shoes contaminated with lube, replace shoes again
4. if both sides are leaking, wrong seal, nicks on journal or bore and /or faulty install
5.pull drum ad operate little cable and verify contact of adjuster arm with star wheel, could be bent from adjustment, happened to me once.
6.verify vent hose is not plugged.
 

Superbond

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so
I just put it all back together. The 4 contact spots. I cleaned up and there were deep groves that I ground gently and filled in with welds then ground down smooth. Added high temp grease. Everything is how it should be. I pulled the vent line and blew it out. It was fine. I will pull the fill plug and let any oil leak out. Then I’ll test her again! If it happens again. I’m going to cap off the back brakes.
 
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