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MG MGA - Frozen Trunnions

I am doing a body off resto (60 w/wire wheels)and now after getting the frame completely stripped, it's time to fix stuff and start reassembling. I decided to start at the front of the car with rebuilding the front suspension. On the right side I got the nut off the upper trunnion and removed the bolt and distance tube. On the left lower I removed the nut and got the distance tube to side out but it permanently frozen to the bolt so I can't separate it fron its lower A-arm.
On the right side things are worse. I can get the nuts off the upper and lower trunnions but that's it. The bolt/distance tube/bushing seem to be one solid unit. I used a braker bar and air hammer and those bolts won't move.
Here's my question. From the parts cat each trunnion shows a bearing (Moss-330-140). Should these simply tap-in/out or is this machine shop work?
Should I be thinking about tossing both king pins and A-arms in the trash and looking around for some used units that I can rebuild (Yes I already bought a Front Suspension kit from SF.) And if so where is a good lave to look?

Another question, should the trunnions turn off the kingkins with the bolt and distance tube out but bearings still installed? I ask because on the left side neither the upper or lower trunnions move more than 15 degrees in either direction.

Opinions appreciated..,
Joe Holtslag

It's been a couple of years since I did mine, but I remember that the trunion had to be pretty much centered on the king pin to avoid running into the king pin threads hence your 15 degrees of movement. I recall having to have one of mine pressed out by a machinist after cutting the bolt head off on the lower unit. Good luck!

Be sure to check Barney Gaylords site. He has a great pictorial on the whole process.
Don Carlberg
Don Carlberg

Have a look at this page on the MGAguru site
http://www.mgaguru.com/mgtech/suspensn/fs201.htm
all your suspension answers can be found in these articles
http://www.mgaguru.com/mgtech/suspensn/susp1.htm
Mike
Mike Ellsmore

On a couple of mine the bolts were also fused to the distance tube. I took an angle grinder and carefully ground the heads off the bolts.

The bushings can be driven out with a hammer and drift, but should be pressed in. I used a large bench vise to press mine in, and then reamed them as shown on Barney's site. If you can get them off the car, don't think a machine shop would charge to much to press in the new bushing and ream them.

As far as not being able to turn the trunion more than 15 degrees, there is supposed to be a hole in the middle of the bushing to clear the kingpin threads. With the distance tube out you should be able to look in or feel for the hole. If it is not there or the bushing is twisted so the hole is in the wrong position, you will probably have to drive the bushing out.


Jeff Schultz

When the trunnion bolts and distance tubes are completely fused and won't budge, start by removing the nuts (break the bolts if you have to, and grind the heads off of the bolts. The frame needs to be on stands. Put a floor jack under the lower suspension arm, directly below the coil spring, and lift slightly. Then remove the front side A-arm bracket (one big nut at inner end plus two small bolts). Pry the lower trunnion away from the other A-arm bracket, then lower the jack to unload the coil spring and pull out the spring. On top you cam remove one arm from the shock absorber, then separate the trunnion from the other shock arm. This leaves the swivel pin assembly with trunnions and frozen bolts free to take to the work bench.

The bolts and distance tubes must be removed from the trunnion before unscrewing the swivel link from the swivel pin. The only thing holding the distance tube into the swivel link is dry hard hardened grease. It should come apart with a big enough hammer. Otherwise heat the trunnion with a torch to hopefully soften the dried grease enough to allow removal of the distance tube.

Aside from the bolt you destroy, the distance tube will also be corroded on the bearing surface, so plan on tossing those in the trash as well. New bolts and distance tubes and sleeve bearings should be included in the suspension rebuilt kit.

To remove the sleeve bearing, use a hacksaw to cut through the bushing wall from the inside, after which it should tap out easily. You might wail on the old bearing with a large hammer and punch for removal, but do not hammer on the end of the new bearing for installation. The new sleeve bearing can be pressed in using a BIG bench vice.

The sleeve bearing is bi-metal with bronze inside of a steel liner. There is a hole in one side that has to be lined up to clear the swivel pin thread when the swivel link is screwed onto the swivel pin, After the sleeve bearing is pressed into the swivel link it has to be reamed to 0.7500 inch diameter. The distance tube will be 0.748 inch diameter to be slip fit with clearance for grease. The distance tube must also be a few thousandths of an inch longer than the trunnion and sleeve bearing so the tube can be pinched tight on the ends in assembly and the trunnion can rotate on the tube. See here: http://www.mgaguru.com/mgtech/suspensn/fs201.htm

Barney Gaylord

Many thanks for the sage advice. I did review Barney's two pages Mike suggested as well as checking the archives before posting but I simply couldn't believe trunnions could rust up that bad. I thought I must be missing something. The idea of grinding the head off a trunnion bolt was not even on my radar. So I take you are saying that after I removed the bolts and distance tubes from my left kingpin, the only thing preventing me from turning off the trunnions was dry hardened grease? I had it in a vice and tried to turn it off with a 24" rebar (of course heating it never occured to me). Well I ordered my reamer today. Again many thanks....
Joe Holtslag

This thread was discussed between 09/09/2012 and 11/09/2012

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