VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1931 rear end vent

I've got my 31 rear end apart to replace gaskets and seals. To stop axle seal leaks it has been suggested to replace inner and outer seals and to replace the bearing with a double sealed bearing. Has anyone tried venting the housing as on later model units, and did it make a difference? All suggestions are appreciated. Thanks

Dick!

Just finished rebuilding the rear end in my 31, replacing the ring & Pinion, both carrier bearings, front & rear pinion bearings and both axel bearings (double sealed). If you have not purchased your bearings yet, you might want to contact George, at OLCAR BEARING CO.
135 James Creek
Southern Pines, N.C.
910-693-3324
He also has the inner & outer axel seals and his prices are very reasonable.

Hoppy, do you have the part # for the double sealed rear axle bearings? Thanks

I rebuilt the rearend on my '31 pickup about a year and a half ago. I was very careful about sealing things up-cleaning sealing surfaces and using the copper spray on the differential cover gasket. I even coated the bolt threads with sealant-I did not want any leaks. We went to a car show about thirty miles away and after I got home and put the truck away, I was looking around for any leaks and things looked good. However, I did hear a very faint "ticking" noise from the rear end area. I crawled under there and tracked the noise to the top of the cover. I got my flashlight, put on my glasses and followed the sound. There were tiny bubbles coming out from around one of the differential cover bolts. The rear end actually was under a slight pressure and was venting. The modern seals did such a good job that I felt that the rear end should be vented. I got one of those small spring-relief vents that you see on modern transmissions and rear ends and drilled and tapped the top of the axel housing near the right spring mount. I cut a little bit of the spring off so that it will vent with the slightest pressure. Dan

Dan that is good to hear, I noticed when I trailered my 28 last week that I had some grease dripping out of the right rear axle housing (around the alimite fitting on the axle housing)I had filled all the gearboxes the day before I loaded the car inside the trailer , I looked for a drip but there were none also midway through the trip there was no leak, but I raised the front of the trailer so that we could use the Tahoe that afternoon and when I unloaded the car that evening it had a small amount of grease that leaked from the alimite fitting. The car didn't leak any more after it was driven.

I probably will need to install a couple of vents, did you get them from a parts store?

What is the number of double sealed bearings for rear axle?
I have looked for then here in Sweden but I can`t
find them. Have Olcar bearing Co E-mail and can
anyone give me the E-mail.What is the size
h=?, H=? and the W=?

Bengt from Sweden

Dan, thats what I wanted to here, great job of troubleshooting. I am unfamiliar with the type vent you speak of. Is it an item I could pick up at the local parts house? I was thinking of drilling a bolt part way thru and then cross drilling it.What do you guys think?

Great info Dan ! I rebuilt the rear in my 32 using sealed bearings and sealed the torque tube and was wondering about pressure building up.I did experience some cover bolt leakage also even after sealing the threads.The vent sounds like a good investment.As for sealed bearing numbers a good bearing company can determine the sealed number from your original bearing number.The standard bearing number will determine the size and the suffix letter the additional specs such as shields,snap rings and seals.For example a 308 brg is plain and 308szz may be shielded and double sealed.different mfgs may have varying codes but a good supplier should be able to identify the correct number quite easily.

The vent that I used was from a Dodge truck rear axel. It takes an 1/8" pipe thread. I believe you can find these at an auto parts store-they may have to look in their parts book and order. Another option for those who may want to retain a more original appearance may be to drill a small hole on the top of the axel housing out near the spring mount and simply install a cotter pin in it. This would be very inconspicuious (you would see the head only) and would keep the rear end "open" to the atmosphere. The cottter pin would remain captive if you pre-bent the legs and inserted it in the hole under tension. There would be no oil slinging around up there like there would be around the pumpkin area.
Dan

That sounds like better KISS engineering anyway!

This is another example of using modern replacement parts. With the felt seals only minimal pressure could build up. With sealed bearings or modern lip seals higher pressures are likely resulting in more modifications. It should be a consideration when making those changes.

In my case it was a new outside felt seal that was soaked in oil for awhile before it was put on, I only drove the car a few hundred feet before loading it into the trailer. The '28 is still in the trailer parked at the curb since I messed up my knee at the very end of the tour, better check the trailer today since it has been jacked up at the front and the rear end is lower than normal.

Dick & Bengt (from Sweden)!!!

Those rear axel bearings (sealed) #1307
Just at note to say you will not have to use the grease fitting at the end of the axel housing anymore. I`ve just talked to George at Olcar Bearing Co. and he is the a Guru when it comes to bearings and he tells me that using sealed bearings in the axels is definetely not the reason for pressure build up in the differential housing. I have them in my car (1931) and have driven it approximately 500 miles since installing them with no leakage whatsoever!! I am now using hypoid 80-90W which would probably be more apt to cause leaks than the 600W, but still I have no leaks. I also used a Chicago Rawhide seal #CR9876, ($4.00 at NAPA Auto Parts) in the front torque tube, which virtually eliminates the transmission gear oil from draining back into the differential housing which can overfill it and possibly cause pressure build-up. The ball joint housing needs to be properly shimmed and sealed also to prevent leaking. The drive shaft bushing in the torque tube also needs to be inspected or replaced if worn.

The #1307 sealed axle bearings are $42.00 ea.

Old Car Bearing Co. e-mail address
brgdr@earthlink.net (George)

Hello Bengt- In answer to your request for size of the 1307 it is 35.00 mm inside diameter-80.00 mm outer diameter-21.00 mm wide-It is listed as being a double row self aligning bearing-My interchange listed several manufacturer's that use it such as volvo-renault-citroen-my 29-38 price list(partsbook) list the bearing as chev# 901307-ND 1307-as this is the original number I am not sure the plain number 1307 is sealed -check with your supplier before ordering.

Thanks for answer!
Here in Sweden are the number 6307-2Z.
That bearing are 80-35-21 mm and that bearing
are std here i Sweden.
So I will try it.
Bengt from Sweden.

Are there some expert final words on using a vent or not?

Gator...
"To vent or not to vent....that is the question?"
If you experiance the same problem of differential pressure by Dan, you do need a vent,otherwise the pressure will go some where it should not go if you do as careful a job as he did to prevent leaks.
I do know that the 53 and 54 axle housings used a vent on top of the left side, so why not vent?

Gator: Don't vent but say that you did vent. Ha ha! :eek: :eek: :p

Think I will wait and see what happens...thanks for the input guys.

I've been gone for a week, just got back to reading all this great info. Thanks to all who replied. I figure a vent can't hurt, so I will vent!!

Question- Hoppy, just where was this rawhide seal installed? Behind the U joint on the front of the torque tube or behind the torque tube bushing? which would require replacing the bushing. Not a fun job.

Dick! Yes, the seal is installed behind the bushing toward the rear of the car. The rivet will have to be removed from the torque tube( I chisled mine off ) in order to remove the bushing,then the old cork seal then a retainer washer. Installation is the reverse. What made the job easier for me was I had the differential carrier and torque tube with driveshaft removed laying on my workbench. This job can be done with a little bit of effort on your part while still in the car. After digging out the rivet that holds the bushing inside the tube you can use an icepick to push it out toward front of car and remove, remove old seal. When replacing install washer first then new seal #CR9876,install closed end toward rear The washer will hold the seal in place,then install bushing lining up the rivet hole and install new rivet (I used 1/4" stock and mig welded it to tube). Yes, it can be a fun job if you just take your sweet time and if you find yourself getting aggrivated, close the garage door, turn off the lights and go take a nap, and dream of "Pumping" new life into a 73 year old gal!!!

It is always a good idea to install a new bushing as well, because the old bushings are usually badly worn. And, if you use an "Oakie" bushing, the rubber seal is part of the bushing assembly.

Thanks for all the good info, now all I have to do is get it done. I've got another question for all you experts. Rear end spring saddles, they clamp around the housing and are held in place by the u bolts. Mine seem awful loose, is there a tolerance spec for this? Thanks ,

Before replacing bushing make sure to measure and inspect the shaft. Many times the shaft is worn and/or rough. Even with a new bushing there will be too much tolerance. It will likely show up as vibration in drive line and eventually leaks in the lip seal.

If shaft is worn you have three options, replace shaft with new one, buildup (welding, hard chromeplating, metalizing) worn area and turn down or reducing shaft size and installing oversize bushing. The first two are recommended. I am not aware of oversize bushings being available so it will require making the bushing brass or bronze insert yourself. You could substitute a bushing for another year driveshaft with some machine work.