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MG TD TF 1500 - Driveshaft balancing???

I've slowly been sorting through various issues with my 53. The last (ha ha) that I still have not resolved is a farily hi frequency vibration above 45mph or so. I tried rolling through this area thinking it might be a harmonic or something but it doesn't quit. I'm thinking that maybe when I did the u joints I got something out of alighment or something. the frequency is not RPM dependent as there is no vibration in the lower gears, only after 45mph. It's also not wheels as the frequency is just to high for that at 45mph. Only thing left that I can think of is driveshaft.

I don't think it matters which end is which on the driveshaft does it? As I revall it can be mounted up either way.

I'll be pulling it off this week and check the u joints to make sure they operate freely. then I think I'll take the whole assembly, shaft, joints, and yokes to have balanced/checked

I'd like to get this fixed so I can go more than 45 mph. Does anybody have any suggestions or feedback on this problem.
L Rutt

Try turning your U joints 180 degrees, some time one can get them on the wrong way and turning them will take care of the vibration. did you have your driveshaft balanced?
Tom Maine (TD8105)

Only advice I could offer seems to be already in your train of thought. Have a shop that does drive shaft balancing do yours. They will also check it for straightness. If it is slightly bent, were talking thousandths, a new tube should be welded in and then balanced by the shop. PJ
P Jennings

The obvious thing is to make sure is that the u joints are parralell to each other,,,AND make sure that the splines are not warn,,,,while it is in the car, try to move the shaft and see if there is movement at the splines....


I altered my search and did find an entry that discusses u joint orientation. I don't think I did that, check the shop manual to confirm. So I'll try that first before the balance attempt.

Should have done a better job of searching.

Seems most answers are there if you just type in the correct words to search by.

L Rutt

You might want to check the U-bolts as well. Several years ago I had u-joints installed in a midget I had and after improper installation they were extremely stiff and made the stump bounce up and down...not good
I had to re-purchase and install the u-joints myself but it also showed that the bolts weren't tight enough so after trying to tighten and breaking the rusted bolts I installed new ones.

Gee...and the garage that messed up the first set of u-joints said my shocks were the problem...

Point is maybe the stump is moving and causing the vibration.
Richard Taylor TD3983

if it is speed related and not drive shaft rpm related why do you suspect drive shaft imbalance. wouldn't drive shaft imbalance occur at the same rpm not the same mph??? regards, tom
tom peterson

drive shaft rpm and mph are directly related. There is a 4.875 to 1 ratio in my car.

I'll be getting under there this weekend to make sure the u joints are parallel. If they are then I'll pull the ds to make sure the u joints are still good but I suspect I did not get them parallel when I installed. Something I overlooked.
L Rutt

Page G.4 of the WSM, Section G.7, Replacement of the Propeller Shaft -- "The sliding joint is always placed at the gearbox end." Bud
Bud Krueger

I had that problem. Drove me nuts for a year and a half!. I was obsessed! Rebuilt everything in the front end.
It came down to the right front shock needed to have a new bearing. It was hard to notice/find but it worked wonders!
Peter 54TF
Peter Dahlquist

i am half way to monroe, wi. on a drive today when it dawns on me that you clearly stated drive shaft in both the title and posting..i read drive shaft but was thinking input shaft..i believe because i am working on another old car with a suspected bent input i am self nominating for dumbest post on the forum ever. my apologies to the group. regards, tom
tom peterson

You had me wondering about you!
Don Harmer

Well damn. U joints were oriented properly and splines are nice and snug. Ujoints flex and move freely.

So it's all off now, I guess I'll get it balanced / checked just to eliminate that.

I hope they can balance the whole assembly with the u joints and end yokes in situ.
L Rutt

L Rutt,

That's exactly how it needs to be ballanced. They ballance the whole thing dynamically. Just bring it in and they'll get er done for ya. From this point forward you'll need to make sure you have a mark for where the splines and shaft meet. If for some reason they get separated, you'll want to make sure they go back on in the same place so the ballance is not lost. Let us know how it went. I'm curious if this fixes your problem.

Alex Waugh

Problem resolved.

Indexed the u joint on the input end 180 degrees. She now blasts right through 45, 50, 55 mph. Start to get a shimmy at 60 but that's ok, I shouldn't be going any faster than that with those 4.875 gears anyhow.

Woo hoo. I'm happy with the results. Quite surprising how easily she spooled right up to 55, 3500 RPM's by my gauges.

Just thought I'd post back to close this thread out for anybody in the future searching on this problem.
L Rutt

This thread was discussed between 04/10/2011 and 16/10/2011

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