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MG MGA - Rear end movement

Cheers -

I brought my car to an experienced British shop for installation of two new rear splined bubs. Fronts were fine. The old hubs were removed and new hubs pressed on. At the same time, I purchased 4 new Minilite knock off wheels for installation on the front and rear (new) hubs.

The minilite wheels would not go on the rear hub splines more that a few inches. The fronts went on without issue.

The shop figured new splined hubs vs. new wheel splines = the use of a BFH. I'm talking BIG F sledge H. They pounded on a 2 x 4 placed over the wheel on the drivers side rear and gained perhaps 1" onto the hub. This abuse was repeated a few more times>. it was determined that the new hub splines were faulty. New hubs ordered and pressed on, problem solved. Wheels slipped on with ease.

So now my rear tires appear to have shifted about 3/8" + - toward the passender side. The passenger tire hangs over the fender well by approximately 3/8"

Could the rear end/axle assembly shift by repeated blunt force with that BFH? Is there a way to measure for the proper centering distance?

Fran
F Valenzano

Any chance you could post the name of the shop in question, so other members in FL will know to avoid them?
Del Rawlins

Fran,
What size rims and tyres are you using? Was there any change in the offset with the new rims?
Mike
Mike Ellsmore

With the exception of this BFH abuse, the shop in question has performed exceptionally well. They have an excellent reputation with British cars. Undoubedly they were frustrated with the misfit hub and took to a cave man approach. I guess we have all been there at one time or another.

The wheels are the correct offset. I am not sure that any amount of repeated blows to one side could cause offset of the rear axle assembly from center. On the other hand could 3/8" of drifting be feasible?
F Valenzano

Hi Fran. It sounds like the sledge hammer pounding has shifted your rear axle out of alignment! This amounts to the shop in quetion doing damage to your car! If this is what has happened, I would have them make any necessary repairs AT THEIR EXPENSE! Additionally I would be worrying about damage to your wheel splines! Trying to pound a wheel onto a wrongly splined hub, could do serious damage to the splines! I think the splines need to be carefully inspected for damage. Again, if there is any damage, the shop in question should have to shell out to put things right. Wheel splines are a big safety issue! If they are worn or damaged, your wheels can literally fall off the car,while driving down the road. This happened to a member of this BBS, and the experience was NOT a happy one! Just my 2 cents worth, GLenn
Glenn Hedrich

Fran,

My guess is that the axle could have shifted on the U-bolts but it is unlikely that the force was enough to bend anything permanently. Have a look at the shackles to see if there's any sign of damage.

I absolutely agree with Glenn that if the shop did the damage, they should pay for rectification. They can't blame the hubs because they should have known that amount of force was excessive and potentially damaging. What if the wheels have been invisibly cracked? I wouldn't drive the car fast without checking. And how did they expect you to get the wheels off again?

Regards

Malcolm
Malcolm Eades

It is well known that the (wider) Minilite repro wheels have the wrong offset and position tires closer to the fenders. The original setup has plenty of clearance between tires and fenders, so it can tolerate a little misalignment of the rear axle OR slightly larger tires (not necessarily both at the same time). However, the combination of incorrect wheel offset and some offset of the rear axle could well lead to a tire rubbing on a fender.

Offset rear axle is usually a result of shifting of the mounting at the U-bolts. The rubber isolating pads are often soft or deteriorated. Tightening the U-bolts can often correct the looseness and restore centering of the axle. New rubber pads are cheap.

Wheel splines are supposed to be hand fit, easily sliding on or off. Anyone using a hammer to force wheel splines together may plead temporary insanity in a court of law, but any resulting damage is still their responsibility.
Barney Gaylord

Guys,


Thanks for all the input. I understand that the shop is at fault for using a mindless approach in trying to mount the wheels on to the hubs. No argument here.

The wheel splines are fine and the wheels have been tested for stress cracks. The faulty rear hubs were removed and two new ones were pressed in place. The wheels can now be removed and reintalled by hand without issue.

To Barney's point, I am experiencing fender tire rub on the rear side opposite where the force was applied. Tires are oversized 195X65X15, however only one side is affected by the rub, and only when the car is driven over a dip in the road. The notion that the rear axle might be out of alignment came to me when I was thinking about the attempted brute force installation on the faulty hubs.

The question is how would I determine if the rear axle assembly is in fact misaligned? Is there a way to take measurements and from what points? If I loosen the U bolts sufficiently, is it possible to realign the axle to center if it is misaligned?

Fran
F Valenzano

Bit of lateral thinking: engineering tolerances on some items of equipment were quite high in the 1950s in the UK. 3/8" may have been within limits on fenders and such like. My old 1948 MGTC had a 1" longer running board on one side. May be worth doing measurements from the car centre line to see if there is a problem rather than just measuring wheel clearances with the fender.

Steve
Steve Gyles

Jack the rear up and place jack-stands under the frame. Look every carefully at the U-bolts, the axles saddles and the axle, does it look like there was any lateral movement? The U-bolts should be perfectly plumb.
David Werblow

I'm glad to hear that the shop did good work, when they were not trying to destroy your expensive wheels, hubs, bearings, and axle housing.
Del Rawlins

Is the distance from the outer U bolt to the brake backing plate on both sides of the car the same (measured with inside calipers)? This will give you a fair idea if anything has moved. Are bushings and pads in good condition?
Mike
Mike Ellsmore

Mike -

Thanks for your comments.

I will attempt to measure the distance between the backing plate and the u-bolt to determine if there was any lateral movement or other obvious misalignment at the U-bolt.

The shackle pin bushing and silent bloc are indeed petrified. The pad sets appear to be soft and severely compressed. It is my plan to renew these items. The leaf springs will need to be removed to replace the bushings, so I will take some measurements at that time (per Barney's article on leaf springs) to see if both springs meet the correct measurements when removed from the car.

Fran



F Valenzano

Looks like there was some lateral movement of the rear axle housing toward the passenger side. Is it possible to shift the assembly laterally by loosening the U-bolts?

Can someone give me the proper procedure to realign the rear axle? We are talking about roughly 3/8"

Fran
F Valenzano

It is not unusual for the spring center bolt to be broken or rusted in half; it all stays in place until it doesn't! And if the springs have not been apart for a long time, the bolt is worn/rusted to the point it will soon break if it hasn't already. Since the pads are bad, replace pads, u-bolts, and center bolt all at once. It is the fit of the center bolt in the pads in the retaining plates that determine axle position. Center bolt is available from any decent auto parts place; it will be too long and you cut it off after assembly.

FRM
Fletcher R Millmore

Makes you wonder what people are thinking,or in this case not thinking.How were you supposed to take the wheel off if you got a flat, carry a BFH with you all the time?
gary starr

I have done plenty of work on my "A", including changing a steering rack and replacing both swivel pins. Admittedly, I have never tackled the removal of the rear leaf springs, which appears to be less involved than the front steering assembly.

That said, what jacking point should I use at the rear? Logically I was thinking that jacking up under the frame will cause the leaf springs to arc without the load weight of the car. The removal of U-bolds, pads and bushings seems straight forward enough, but where to jack uo the rear is my question.

Any thoughts?

Fran
F Valenzano

While you are in there, remove and replace the U bolts and when you do, lever the axle over the way you need it to go (there usually isn't much leeway, but all you need is a little) before tightening the new ones up. If you were running 165 tires you probably wouldn't have a problem. All MGs seem to have a slight offset one way opr the other.

Unless the old U bolts were loose, I doubt they moved the whole axle by beating on it. I'd wonder if they hadn't spread the splines though. With the spinner off, move the wheel back and forth on the new rear spline. Now move one of the front wheels that they hadn't buggered about with to the rear and if the amount of play, which should in any case be quite small, is less, I'd start wondering if they hadn't hurt the new splines on the rear, or maybe just the one rear - in which case they should be paying for a new spline insert.
Bill Spohn

Fran...

I just did mine a couple of weeks ago. I jacked from just aft of the spring retainer plate until I could get a sturdy jack stand to support the frame forward of the spring eye mount forward of the axle. I then used a second jack to support the axle between the differential and spring plate.

After loosening the u-bolt nuts, I used the pair of jacks to alter the tension between the axle and leaf spring. After getting separation between the spring perch and leaf spring, I removed the loosened u0bolt nuts, u-bolts, axle stop, retainer plate, and spring pads.

I was doing shackle and spring eye bushings, so I continued on to remove the shackle bolts, then spring eye bolts.

I also used the opportunity to clean and freshen up the paint on suspension components after wire brushing everything since I had good access.

All in all, not a bad job...you may fight with some stubborn/rusted bolts, especially if you go ahead and remove the shackle and spring eye bolts.

Assembly is the reverse of removal. I was a little frustrated in not finding torque specs for tightening everything back up. Barney was kind enough to reassure me that I wasn't missing anything, and I just needed to tighten 'firmly' and recheck in a couple of hundred miles.

Good luck!
rpb bunch

Rpb

Thanks for the step by step. I should be able to renew the springs and other components based on your methdology.

Fran

F Valenzano

I jack my car under the diff centre with a trolley jack to its maximum lift and then put wood blocks under the chassis rails forward of the spring mount where is straight. These blocks have a routed slot along the top to fit the raised seam on the chassis rail. The top of the blocks have a slight angle to the base so that they match the angle of the chassis to the garage floor (Blocks are substantial 100 mm x 200 mm x ~350 mm high). When blocks are wedged in place and front wheels choked I let down the the trolley jack (it can then be used to lift spring slightly on the side you are working on). I also put axle stands just forward of the wooden blocks as extra safety measure (adjusted as close as possible but not touching).
Mike
Mike Ellsmore

This thread was discussed between 08/05/2010 and 16/05/2010

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