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MG TD TF 1500 - Front end vibration
|I'm going to rebuild the front suspension on my late model TD. I have a shimmy at about 52-55 MPH which doesn't appear to be the cowl shake that has been mentioned in the past. I have tightened all of the bolts on the firewall, towers and hoop, fenders, rebushed the steering wheel column, had a precision balance put on the tires, packed all fittings with grease, and in general tightened any bolts that are on the front of the car. I have rebuilt shocks all around as well. I've checked the runout of the wheels themselves and they are all less than 1/8 inch. The only other things that I can think of that are left to do are to install new poly bushings on the A-arms and pins/bushings on the upper and lower links. Are there any other wear items that I should be looking to replace. When I have the car on jack stands there is no movement at all of the wheels in any direction. I don't know where the play is coming from to allow the front end to develop the shimmy. I've tried to drive thruough the vibration but it still is there even when I get it up to 60+mph. Any input would be welcomed.|
|If all else appears tight with no lost motion, the next stop I would make is to have the tire balance checked.|
|Mark. I had the same problem and it was a combination of the rims being out of round and the tires themselves. It was solved by having the tires being trimmed to round. |
Eventually I had to replace the wheels and tires. The side runout was fine but they were not round.
I had the tires balanced a second time by another shop with the same results and also rotated the tires around the car in different positions. It's hard to believe that all combinations of tire placement resulted in the same symptoms. That's why I'm reluctant to think that the problem is balance or out of round rims. Could be possible though. I have also replaced the tie rod ends. I have checked the trueness of the tires also. They run very close to true on the outside diameter surface as well as on the sides. I'd really like to think that the problem is just parts that can be replaced but I can't think of any other parts other than those mentioned that might be causing the problem. I guess that if I replaced the mentioned parts and the problem still existed, then I'm back to tires.
|Tire balance can make a world of difference.|
The Workshop manual calls for Zero toe-in, but I tweak in just a touch of toe-in. A toe-out condition will invite hunting- shimmy.
I measure front of tires and back of tires with a tape measure. Crank one or both of your tie rods in for maybe 1/4" narrower in front of tire versus rear of tire (that's only 1/8" change- 1/8" in front and 1/8" in back)). While you're at at, you might use the opportunity to center your steering wheel (crank one side in while cranking other side out).
|JIM NORTHRUP SR|
Did you check for play in the links on the king pins?
Jack up the wheel till clear of the ground and see if you have play in and out - top or bottom in the bushings. Packing them with fresh grease may not work under load.
Also as you said new Polly bushing may help the geometry.
Still sounds like wheel balance though... Can you borrow a couple of wheels for another MG'er near you and test with them?
Just a though.
|R D Jones|
I'll check the toe in again. I checked this fall and it was good. I did jack up the car two weeks ago and checked the play. There was none that I could notice. It might make sense to borrow a couple of tire/wheel assemblies from another car and see what happens.
|Mark, here is a little test that will not cost you anything; try raising the tyre pressures by 10PSI and see if you still get the shakes (the car that is!). Yes, it sounds like poppycock, but it sometimes works for me. A car that spends a lot of time parked can get flat spots on the tyres, even if they are balanced.|
|Could it be the tail shaft out of balance? Probably the wrong area of the car though.|
|Tire balancing is usually not achieved by using weights. I'm not speaking of the wheels, just the tires. To achieve perfect tire balance, shaving the tread is the most workable method, combined with a trued and balanced wheel, you will not believe the difference. If your in the Greensboro North Carolina area, contact Alan Hendrix of Hendrix Wire Wheel service. Alan not only trues the wire wheel within thousands of an inch, he also "tunes" the spokes so they all sound the same. When my MGB left his shop, it drove and handled like a new car. The improvement was amazing. His balancing machine is set up for splined wheels also. PJ|
|What brand of tires?|
|I forgot to say, I installed new Vredestein tires. I was amazed just how much they were out of round and out of balance. After being shaved, there was not even the slightest vibration. PJ|
|I put new Nexen tires on the car when I got it after having the car sit for 21 years prior to my purchase last year. The steel wheels all appear to be true. Paul, I agree with you. When we used to do SCCA racing we had the tires prepared as you said. Never had any problems but we sought a different level of performance. I'd do that here in Williamsburg if there was some place close by. |
The general opinion of the forum seems to be balance rather than mechanaical wear. Probably won't hurt to do the bushings and pins as a matter of routine. It's no big deal. I'm going to try the local Porsche shop to see if they can shed any light on this. Perhaps they can check and put on a better balance to see if that helps prior to a trip to Greensboro. I'm going to tweak the toe in a bit from the neutral postition that it is currently at. I'll also try the over inflation just for kicks. I'll borrow a couple of tires from my other TD which has bias plys to see if the problem is tires or wear. I can run it up to 65+ with no problems. I guess that that will answer it once and for all. Sure wish that they still had the old equipment that we used to use to balance tires with the tire on the car. Seemed to work every time. Have to wait for the temps to get a bit better for the test drive. The above agenda will keep me busy for a while. Also, have the wife wanting to get Xmas decorations up. Have to keep her happy as you can well agree. I'll keep everyone posted.
|Had the same problem. During the resto I left out a part that supports the steering column in the A-arm. I installed it and it did seem to help the problem.|
|Glenn's MG repair balanced the front drums on my car and that helped. I still have some vibration/cowl shake/shimmy, has always been there to some degree since the car was purchased in the 70s. By eyeball, I jacked my car up, rotated each tire against a straight edge, and put the two with the least run-out on the front, which also helped a little. I think I read somewhere recently that the center holes in our rims are not exactly centered, and rigging up a balancer adaptor using the bolt holes more accurately centers? I'll have to find that reference. I also lament the passing of the balance on the car equipment, that was the best. George|
Please let us know what part you are referring to (in part left out)
|Probably completely unrelated but I get a pretty severe vibration (not a shimmy) if I don't do a fast double clutch into 4th and have the engine reved up to pretty close to running speed so the clutch engages without any slippage or stress.|
|J K Chapin|
|Have the wheels checked for runout and roundness without the tyres.|
You can balance a wheel on the machine but it won't stop the wobble if is not round...
It is possible to get the wheels themselves straightened. You just have to find the right person to do it.
The 'fix your alloy wheel' guys mostly can't. Alloys are a lot softer so their presses or experience won't cover it.
In the US you should be able to find someone to do it though. There wasn't anyone in the whole of Ireland who could :(
I ended up buying four extra wheels from a company that did MG wire wheel conversions and despite there claims to the contrary two of the wheels they sent were worse than the ones I had. The others no better.
A local 'fix your alloy wheel' guy took pity on my and made a reasonable job of the best four in the end. Lots of heat and patience.
Have the wheels checked to at least eliminate them otherwise you could be chasing your tail for a long time.
Bad wheels will ruin good new tyres...
You say you've checked the runout and all are less than 1/8". 1/8 seems like a lot to me, I'm sure mine are better than 1/16", Vredesteins, and still get a little bounce at 55-60 mph. Wire wheels, also true to within 1/16, still not as good as I'd like. I "hand balanced" the wheel/tire assys after the "vendor" did, and made them better, by using front spindle, making sure no brake drag, and spinning to note the stop position. Apply weights & try agn, many times. Not very scientific, takes a little time, but helped. That also adjusts for any out of balance in the drums.
54 TF "Emma"
|A W Parker|
You have a clutch disc that has started to seperate (die) I had the same thing one weekend in Rome Ga. and drove it back to Florida. On tear down there were cracks in the springy section of the disc center.
|Wish you hadn't told me that :-( Took it out for about 30 miles this afternoon and it's really runnig good. Retirement happens in May so I hope it can go that long withour flying apart. Only broken bone I've ever has was the tip of my (let's just say middle) finger that I dropped the tranny to that '52 Plymouth on. Does a clutch replacement require the engine and/or tranny to be pulled out?|
Seriously tho, thanks for the heads up.
|J K Chapin|
|Sounds like balance or out of round condition. Some tires will test perfectly round when checked , but when up to speed the centrifugal force can take the tire to a "out of round" state. Their are new tire balancing machines that put a load on the tire, ( I believe this is some sort of drum that pushes on the tire) to simulate road loads. Ask your local tire shops about this. If they don't know about it, move on.|
Drums can also be out of balance, and that is easy to check. Just remove the wheels and spin the drums and see if they settle to the same spot every time. Balancing drums is not so easy as many shops cannot do it as drums now are balanced by the manufacturer during the manufacturing process.
As talked about by others, a 1/8" toe-in also helps. As does checking the "U" bolts for tightness on the rear axel.
TD's are reliable little cars and run well for a long time when set up. My guess would be the tires go 'out of round" at speed.
|I think it was 23-051 or 23-071 plus associated nut, bolt, spacer, at Abingdon Spares' TD Steering page. I don't think Moss listed the part.|
|I had a car a long time ago(not an MG) that had a persistent front end vibration - so I thought. The vibration was only from 55 - 60 mph. It cleared up when I replaced the u-joints in the drive shaft. They were original to the car and did not have zerk fittings. Might not be the cure-all, but worth a check with your grease gun. |
|I put an indicator on the wheels tonight and found that the runout on the wheel rims was less that 1/16 th inch on both the radial and axial positions on all four tires as I rotated them. Have to assume that the runout is okay and that the wheels are good. I adjusted the toe in to give me about a little less than an 1/8th inch per Jim's suggestion. The weather is supposed to be okay tomorrow so if I get time I'm going to try to warm up the tires with a little run and see just how far out of round the tires are using an indicator. They have been sitting for a while and will have flat spots by now. I'll also try the added pressure that Matthew suggested. It won't hurt. I run 32psi at the present time and like the handling. Little steps to address some of the suggestions.|
|Mark, Once I had a similar problem not with a MG but car with similar symptoms as you discribed.|
Went to several companies and asked for help. They all re-balanced and again and again. The all checked for out of round etc, Conclusion : nothing wrong with the tires or the rims. What next to do.. finally I decided to give it another try and went to a shop a I have seen before in my city.
They took the job on and within 20 minutes they handed me the key's with the words .... If the problem still exists you owe us nothing UH !!!
Drove it and the shake / shimmy was gone. What the heck have you guy's done ? Hmm the mechanic said we placed the lead weights on the inside of the rim instead on the outside . I paid my bill with a great smile . Maybe this could help you to.
|Good day all:|
Mr. Strang, just a passing thought, what is the ware condition on/of the front engine mount ?
Jack Emdall, TC6768/TD3191, Halfmoon Bay, British Columbia, Canada
I'm curious. What would the front engine mount have to do with the vibration?
|I have tried everything to get rid of this vibration/shimmy,,, The only thing that works is to drive either slower of faster that 50-55!!!|
|Dave Braun was most generous with advice for me some time back. He commented on an obscure vibration phenomenon discussed in a T restoration book (expensive book). You have to drive thru 55 as you mention. I think it had something to do with the steering rack. As I said he is generous with his time with T owners. Maybe an e-mail to him is in order? |
|Well, it is beginning to look as if the majority rules. I took the two front tires to a shop that I trust. The owner put the first tire on the balancer and the wheel was clearly out of true. The second tire combo ran very well with little if any out of roundness. I guess that I'll take the other three wheels/tires to him and see if I can find another tire that is good. Then I can mount the best up front and see what happens. I have two spare wheels that he can check as well. Might end up with four good tire/wheel combos. If that is the case, the rebuild of the front suspension will be a minor deal. It really bugs me that the previous shop didn't tell me that the rim was out of true. I guess I should have stood there and watched myself. It would have solved a lot of problems if in fact the current approach works.|
|I think Peter might be referring to the inner ball joint of the steering rack. These can be tightened by removing the ball cover and sanding the edge down until it makes a tighter contact with the ball, Horst Schach covers it in his book pretty thoroughly.|
Someone mentioned that the wheels are lug centric, not hub centric. In other words, if not balancing them off the lugs, and instead using a cone device to center on the center opening, you can be far off on your balance. You need someone with the correct lug spacing mounting tool for their balancing machine.
Finally, if you can locate a shop with a road style balancer (see below), and spin the front wheel with the wheel on the car, you can find out if you have a balance problem or not. Just put a gallon jug of water on the bonnet and watch the vibration resonance in the jug.
Most of our balance problems are on the front wheels. the rears seem much more forgiving. Go to my website in the 'ongoing maintenance >> Lug Centric Balancing' section for more descriptive pictures.
With reference to my writing regarding the front engine mount and subsequently the stabilizer assembly, which I did not note, I thought being that as most of the other possible areas of the enquiry were being covered that a vibration produced by the above may have travelled along the frame rails to give a false feeling of front end wobble, etc.
Obviously that was wrong. Sorry.
No apologies necessary,,, ANYthing to solve this shimy/vibration is a worthwhile suggestion!!!!!
MGTD52 at comcast dot net
If you have tried all the other suggested remedies and you are still tearing your hair out,you could try swopping the front brake drums to the other side. I cannot tell you why this should work only that it did for a friend who went through the suggested solutions that you have tried so far but still could not eliminate the problem entirely.
This vibration at around 55mph does seem to be a regular occurrence with TD/TFs but reading other forums indicates that it can affect MGB/MGCs as well.
|Well, the story ends. I took all five wheel/tire combos to my old tire shop and we spun them all up. I learned that they can be in balance but that there can be an out of round condition that really shows up at speed. I suppose that this is where tread shaving comes into play. We selected the two best of the bunch for the front which included one that was almost perfect and I installed them this morning. I took it out for a test ride and Max zipped right up to 65mph with no vibration!! The little guy really wants to go. I also have two spare wheels that we spun up with no visible runout. I guess I'll get these blasted and painted and swap out two of the rear wheels for these. I should have a good set of wheel/tires after all of this. Thanks for all of your help. I'm still going to replace the bushings and pins this winter but at least I won't be looking for a needle in a haystack trying to figure out the source a problem that didn't exist. The idea of replacing the front engine mount is a good one since it is original and probably not in very good shape. Is it possible/pratical to replace it without pulling the engine? Is ther enough play in the rear mount to allow me to slip it in?|
Thanks again for all of the help as usual. I got some real good ideas out of all of this and as usual learned a lot.
This thread was discussed between 01/12/2013 and 03/12/2013
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