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rear wheel bearings

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Hot Spit Avatar
Hot Spit Mike Stefanakis
Wethersfield, CT, USA   USA
In reply to # 1587422 by Hot Spit
In reply to # 1587238 by Hot Spit Guys,

What do you think if I block up the front wheels and jack up the back one side at a time and run each axle up to 40 mph? That should isolate one side from the other. If no vibration I'll look at the u-joints. BTW the wheels have been balanced.

Is this a crazy idea?

Mike

This little test run proved to be inconclusive. Without a load on the wheels all the backlash in the various parts of the drive train have a tendency to rattle hiding any vibration that may be present. I'll look at the u-joints next or maybe drive it the way it is to get more miles on the Carterized axle. I have to think about it.

Mike

Today I redid the same test, as above, only I pre loaded the wheels one at a time by taking up on the brake adjuster so that the backlash on the drive line would be taken up. I was hoping the the problem would show up in one axle or the other. The result was the same. When I turn things by hand everything turns and feel smooth, under power a noisy vibration.

While on the stands I got under the car as it ran in first gear, (not recommended) and the problem seems to be in the Diff. I will disconnect the axles and and run it again. Rats!!

Mike



Edited 1 time(s). Last edit at 2019-01-05 05:37 PM by Hot Spit.

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Hot Spit Avatar
Hot Spit Mike Stefanakis
Wethersfield, CT, USA   USA
In reply to # 1587656 by Hot Spit
In reply to # 1587422 by Hot Spit
In reply to # 1587238 by Hot Spit Guys,

What do you think if I block up the front wheels and jack up the back one side at a time and run each axle up to 40 mph? That should isolate one side from the other. If no vibration I'll look at the u-joints. BTW the wheels have been balanced.

Is this a crazy idea?

Mike

This little test run proved to be inconclusive. Without a load on the wheels all the backlash in the various parts of the drive train have a tendency to rattle hiding any vibration that may be present. I'll look at the u-joints next or maybe drive it the way it is to get more miles on the Carterized axle. I have to think about it.

Mike

Today I redid the same test, as above, only I pre loaded the wheels one at a time by taking up on the brake adjuster so that the backlash on the drive line would be taken up. I was hoping the the problem would show up in one axle or the other. The result was the same. When I turn things by hand everything turns and feel smooth, under power a noisy vibration.

While on the stands I got under the car as it ran in first gear, (not recommended) and the problem seems to be in the Diff. I will disconnect the axles and and run it again. Rats!!

Mike

Removed the axles and ran it up with only the Diff connected. It did vibrate but not as loud or as severe as when the axles were connected. When there is a load on Diff it's worse. Both axles are out now and I will be dropping the Diff to take a look. The test on the Carterized axle will have to wait for now.

Mike

Hot Spit Avatar
Hot Spit Mike Stefanakis
Wethersfield, CT, USA   USA
Well the suspected criminal is out and I'm tired. What I was able to do in a day now takes me a week. I have no trouble getting down and under the car, getting back up is the problem. When I open puppy up I hope I find something obvious or I'm going to be PI$$ED. I'm going for a walk now.

Mike

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clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1588301 by Hot Spit Well the suspected criminal is out and I'm tired. What I was able to do in a day now takes me a week. I have no trouble getting down and under the car, getting back up is the problem. When I open puppy up I hope I find something obvious or I'm going to be PI$$ED. I'm going for a walk now.

Mike

Yeah, funny how the distance between 'down there' and 'up here' increases each year.
Good luck with the inspection.

sampattr250 Avatar
sampattr250 Sam P
Harwinton, CT, USA   USA
Mike,

Excellent work.

I always look forward to seeing your car at Wickham Park.

If your project works I may be doing my rear diff and bearings next winter.



Sam

1968 TR250
1972 MK IV Spitfire

Hot Spit Avatar
Hot Spit Mike Stefanakis
Wethersfield, CT, USA   USA
I am at a loss or perhaps a better way to say it "I'm Lost". After removing the axles and the drive shaft and checking all the universal joints by hand, on the bench and held in a vice, I could detect no shake or movement. They articulated smoothly with no tight spots. So the obvious, to me anyway, the problem was the Diff. So I opened it up to take a look hoping to see something obvious. Nothing stood out as all the bearings were intact and rolled smoothly. No teeth missing no excessive end play that I could tell. One concerning observation was what I saw after straining the Diff oil thru a coffee filter. I still think the problem is in the Differential.

Any thoughts, anyone?

Mike


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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, BC, Canada   CAN
Residue from the fibre TW's that are now bronze?

Is the stuff metal ?

Were you able to measure any run out at the wheel before you pulled things apart? I'm thinking, could a flange have got bent while pulling a hub?

14GPDJENGINEERING Avatar
Silver Spring, MD, USA   USA
Do you have a magnetic drain plug? Any metal on it?



Dennis smiling smiley

clshore Carter Shore
Beverly Hills, FL, USA   USA
What driveshaft style do you have?
Strap, sliding spline, CV joint?
Those can develop wear that allows running out of center.
Does not take much to create vibration.

Hot Spit Avatar
Hot Spit Mike Stefanakis
Wethersfield, CT, USA   USA
In reply to # 1588551 by 14GPDJENGINEERING Do you have a magnetic drain plug? Any metal on it?


In reply to # 1588540 by Tonyfixit Residue from the fibre TW's that are now bronze?

Is the stuff metal ?

Were you able to measure any run out at the wheel before you pulled things apart? I'm thinking, could a flange have got bent while pulling a hub?



In reply to # 1588588 by clshore What driveshaft style do you have?
Strap, sliding spline, CV joint?
Those can develop wear that allows running out of center.
Does not take much to create vibration.

Tony, Dennis what ever that is in the coffee filter it's non magnetic. The inside of the Diff housing seems to have a coat of black paint. Don't know if the factory coated them as a seal for porosity or it was done later. Also the drive flanges are good.

Carter, the drive shaft is a modified Toyota shaft that came with my donor engine and transmission. It was professionally shortened and balanced. The flange from the Spit drive shaft was utilized to mate with the Diff. At this point I will have the Diff carefully inspected by someone who knows what to look for.

Mike



Edited 1 time(s). Last edit at 2019-01-11 07:44 AM by Hot Spit.


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spitfire50 Avatar
spitfire50 Paul Mugford
Rochester, N.H., USA   USA
In reply to # 1588640 by Hot Spit
Tony, Dennis what ever that is in the coffee filter it's non magnetic. The inside of the Diff housing seems to have a coat of black paint. Don't know if the factory coated them as a seal for porosity or it was done later. Also the drive flanges are good.


Mike

Mike,
That black paint is from the factory. It is there to seal in any stray casting sand that might not have been cleaned from the case.
All the best,
Paul

Hot Spit Avatar
Hot Spit Mike Stefanakis
Wethersfield, CT, USA   USA
The differential is back from Quantum Mechanics. I asked them to completely disassemble and inspect all the all the internals. There were a number of issues including some damage to the carrier cluster but one that struck me as odd was a bearing that had an outer cone made by a different maker from that of the bearing and the wear pattern was not uniform across the cone as you may expect. The temperature this morning registered 2 deg so you know I stayed in bed. Maybe I'll get back to it next week, they say 40-50 deg. I can live with that.

Mike

My1976Spit Rick S
Sun City, AZ, USA   USA
I DONT UNDERSTAND THE PROBLEM..........WHY NOT JUST GREASE THE BEARINGS EVER 2 TO 3K MILES....IT ONLY TAKES A FEW MINUTES......THEN U SHOULD NOT HAVE ANY PROBLEMS.........RIGHT?????

Hot Spit Avatar
Hot Spit Mike Stefanakis
Wethersfield, CT, USA   USA
In reply to # 1593683 by My1976Spit I DONT UNDERSTAND THE PROBLEM..........WHY NOT JUST GREASE THE BEARINGS EVER 2 TO 3K MILES....IT ONLY TAKES A FEW MINUTES......THEN U SHOULD NOT HAVE ANY PROBLEMS.........RIGHT?????

Yes, in a perfect world.

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1593683 by My1976Spit I DONT UNDERSTAND THE PROBLEM..........WHY NOT JUST GREASE THE BEARINGS EVER 2 TO 3K MILES....IT ONLY TAKES A FEW MINUTES......THEN U SHOULD NOT HAVE ANY PROBLEMS.........RIGHT?????

In theory, yes.
But the design employs an inner needle roller bearing that uses the axle shaft as the inner race, and it's really too small and highly loaded.
Eventual failure is almost certain, which results in damage to the axle shaft surface.
Disassembly is difficult, requiring a special tool, and often results in damage to other components.
Replacement axles are still available, but who knows for how much longer, the very newest of our cars is nearly 40 years old.

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