7 1/4 Rear End clean up/gasket questions

Hi Guys I am restoring my 65 Barracuda. I dropped the 7.25 rear end out of the car. I know that lots of guys here think they are junk, but I own it..... along with 5x4 wheels. I have ordered new leaf springs and Bilstein shocks. My plan is to clean things up, seal things up, rebuild the rear drum brakes and get on with my project. The first image is right after taking off the diff. cover the first time. Drained the oil, no metal at all, gears look sharp and there is only a very small bit of slack as I turn the pinion yoke back and forth...Backlash right? This is all very new to me, so excuse any mis-named parts...I am learning as I go.




My questions are these:
Which seals should i replace and how do I get to them? Pinion oil seal looks like it has been leaking. I am hesitant to just take off the pinion nut and causing a problem based on my research here. I also want to install new axle seals and of course re-seal the diff. cover. I have been scouring the web site and I can't find out how to actually get to these items with the least amount of disruption to the gears. Also the rear brake T which mounts to the axle is screwed in and has what appears to be a free spinning cap on the top. This must be original and correct, just wondering about what is the purpose for the "vent cap"? Thanks guys...Merry Christmas.

You said it " vent cap " Make sure that it is loose and not clogged or you will get seal leaks elsewhere. Work similar to the old road pipe. It allows pressure to vent to the atmosphere. Just high temp silicone to seal the diff cover.
AXLE, REAR W/DIFFERENTIAL AND CARRIER CHRYSLER 7 1/4 N-1

All of the seals you asked about can be changed easily without disturbing the gears except the pinion seal which is easy just hast to have the yoke torked back to specifications.

Biggest problem with the 7 1/4 is the spider gears, and yours look great. Nothing wrong with a 7 1/4 that has stood the test of time ruffly 54 years old. Unless you throw 300+ rear wheel horsepower to it. Clean,inspect,install new seals and maybe new axle bearings and with fresh lube you'll be good to go.

remove the axels and press on new wheels bearings and seals while its apart.

66jim said:

remove the axels and press on new wheels bearings and seals while its apart.

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I respectfully disagree sbout automatically replacing the bearings. Clean and inspect the rollers and races. They most likely are the original made in USA Timkens. The good ones. Unless they are bad I'd reuse them as new ones made be of questionable quality.

The dual purpose axle vent needs to be clear. In use, the internal pressure of the housing fluctuates as the temp increases and decreases. If the housing was totally sealed, the higher pressure would vent out though the axle and/or pinion seals.

I replaced the pinion seal in mine...to make sure I torqued the nut correctly, I just marked two spots with a centerpunch, one on the pinion shaft and one on the nut. Then, when I was finished installing the seal, I torqued the nut just past the marks. That nut is torqued to something like 250 lb./ft., so you probably don't have a torque wrench for it, hence the marks.

Additionally, I found that getting the axles out of the housing is a BEAR on a 7 1/4. I use an old 13" rim and a sledgehammer to pop then out after removing the nuts on the housing ends. Of course, that doesn't apply if yours is a c-clip axle (I think they changed them at some point...I might be wrong).

If you find shoulders or steps in the bottoms and ends of gear teeth, that indicates how much metal has worn away. That's where the backlash comes from.

Thanks guys,
I took out my rear axles without any big problems. Now I need to source new oil seals for the driveline and wheel bearings. I would like to buy a complete kit if possible. One of the few things that I have found damaged on my car is one of the wheel bearings is flopping around and loose...obviously needs to be replaced. Also gear oil in the brake drum area.....new oil seals. I don't have too much anxiety about the pinion oil seal as long as I get the retaining nut back into its original position/torque ....correct? Source for that part?
#1 How do I remove the oil seals from inside of the rear axles? Old school, using a chisel or screwdriver to bend and dislodge? I can install the new oil seal myself, looks pretty straightforward.
#2 How do I remove the retainer to get to the wheel bearings? I would like to only have a machine shop press in the new collar and bearings, not remove the old ones.
#3 Took forever to scrape the super thin gasket material off the diff cover and get it clean. There were remnants of RTV gooped around the perimeter. What is the best gasket to use here? Add RTV or not?
Again, many thanks........Merry Christmas eve!

JeffreyLee said:

Thanks guys,
I took out my rear axles without any big problems. Now I need to source new oil seals for the driveline and wheel bearings. I would like to buy a complete kit if possible. One of the few things that I have found damaged on my car is one of the wheel bearings is flopping around and loose...obviously needs to be replaced. Also gear oil in the brake drum area.....new oil seals. I don't have too much anxiety about the pinion oil seal as long as I get the retaining nut back into its original position/torque ....correct? Source for that part?
#1 How do I remove the oil seals from inside of the rear axles? Old school, using a chisel or screwdriver to bend and dislodge? I can install the new oil seal myself, looks pretty straightforward.
#2 How do I remove the retainer to get to the wheel bearings? I would like to only have a machine shop press in the new collar and bearings, not remove the old ones.
#3 Took forever to scrape the super thin gasket material off the diff cover and get it clean. There were remnants of RTV gooped around the perimeter. What is the best gasket to use here? Add RTV or not?
Again, many thanks........Merry Christmas eve!

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1) Lisle 56750 Seal Puller or carefully pry them out.

2)What I paid for axle bearing Remove and replace
Axle bearing and retainer RW6-11 2x (RWF34R) $18 + $43 press

3)Rear gasket FEL-PRO RDS12775, I install mine dry. $4 at rockauto

Realize this is an old thread but I have a related question. My 7.25 differential cover had a gasket around the drain plug and I can't seem to source a replacement. I have the case gasket and other parts. It doesn't seem like anything special, just a round gasket but I looked around online and brought it into Napa with no luck. Any suggestions? Thanks!

My 7.25 has a nylon washer on the fill plug. @ 3/4” ID, 1” OD. My local Ace hardware has em.

geminimotors said:

My 7.25 has a nylon washer on the fill plug. @ 3/4” ID, 1” OD. My local Ace hardware has em.

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Thanks! I'm no stranger to buying car parts at the hardware store and in fact I have to make a run there for a random assortment of nuts and bolts anyway, so I'll grab one of these while I'm there.