VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1929 Rear End "Clunk"

I've noticed twice now when I go out for a putt in my '29 coach. I here a rather disconcerting
"clunk" noise when I first let out the clutch. :confused: I do not hear it while going down the road, shifting gears or just cruising. What could it be: :confused:
1. Worn ring & pinion? :confused:
2. Worn rear axle? :confused:
3. Rear service brake bands to tight or to loose :confused:
4. Or???

Since I bought the car I have gone through the front end but have yet to check out the rear end except for adjusting the rear service brakes. Anybody got any idea's?

Hi Captain Harley,
You might have a rear wheel hub loose on its axle taper,or a worn hub keyway.If the keyway is O.K.,you could lap the wheel hub to the axle taper using some fine valve grinding paste to get a good fit of the internal hub taper,and the external axle shaft taper.Don't forget to remove all traces of grinding paste.
I've used this method on my '28 truck and my '29 Olds Sedan,and no problems now.

:)

Kevin, Wow!

Try the easy stuff first. I have found rear brake hub wear to cause the problem also. If that is the problem it typically clunks when first engaging the clutch and also after backing against resistance. I have found that it rairly clunks when letting out the clutch to back up but only when going forward. Apparently the slipping or stop of the slipping is more gradual in reverse. You can also have a machine shop cut another key way 180 degrees if the original is too damaged.

If lapping and a tight key does not cure the problem. It could be loose, worn or mis-adjusted ring gear in the rear end. I had a '28 Chev that had a warped ring gear that was also loose. Twisting of the axle shaft splines is common. I have not found spline wear between axle and spider gears to be a problem. I once had a problem with wear between a clutch plate and transmission input splines. I have some used clutch plates that the teeth on the clutch plate hub are nearly razor thin. Makes the plate junk and noise likely. A dry, worn u-joint would likely cause a vibration before a audiable clunk. Of course the splines between the drive shaft and u-joint are another possible cause.

Good luck. An article in the G&D on what you found and how it was fixed would help many others with a similar problem.

Chipper, Thank you for your advice. It will come in handy when I do work on the rear end. Unfortunately it might be a while before I can start. I'm in the process of buying and selling homes. Moving to another part of the state, etc.
But the new home will give me the shop space I
will need: indoors (no acorns hitting me on the head while working), all my tools handy, and so on. I'll have many more questions to ask and really appreicate the help I get. Thank you again.
:) And, yes I might
even try my hand at a tech. article in the G&D...

On that post from 2005, about the 1929 rear end "clunk", did you ever find out and fix what it was? I have the exact same noise in my 1930, and it's getting louder every few months. Any suggestions will be appreciated.

First thing to do is to make sure the "Clunk" it is in the rear-end and not the universal joint. I have found several U-joints from that era to be the cause of a relatively loud "Clunk".

I have just been chasing a rear end clunk also, and also checked axles, splines, wooden wheels etc. I discovered that with the wheels off the ground (i.e. rear end jacked up) and the hand brake slightly binding, you hear a loud metallic clunk when you rock the wheel back and forth by a couple degrees.

It was caused by the whole inner brake shoe (one piece) rotating with the drum and the end of the shoe hitting the metal stops on either side. With the hand brake hard on you can rotate the wheel slightly with no braking effect, which caused me some initial concern but now I understand and it is not a problem. Depending on how close your brake pad fits the drum and how tight you have the hand brake adjusted, how far it moves.

Sometimes when I change direction (i.e. reverse out of the garage and then drive forward) I hear the clunk, but now know that it is caused by a very slight bind in the hand brake. I would certainly recommend checking for other things as previously suggested, but if you don't find anything then this could be it. I took a heap of photos to show what is happening and happy to post if anyone interested.