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MG MGB Technical - Front Cross Member

Hi

I have a 74.5 MGB Roadster and the front cross member pads are original.
It was easy to loosen the top 4 bolts of the cross member and I was wondering if replacing the pads would be a simple matter of releasing all the nuts, pushing the bolt through and then use a small wedge to separating the cross member from the body and replace the pads without having to totally dis-assemble the cross member?
The rest of the rubber on the cross member was replaced not long ago. I would replace the pads with polyurethane of course.

Thanks

Bruce
Bruce Mills

Bruce-
Yes, you can do it in the manner that you've described. Just be sure to suport the crossmember at each end with a pair of strong hydraulic jacks and lower the crossmember just enough to remove the old pads and then slide the new ones in. In my opinion, the Australian company SuperFlex makes the best polyurethane items, and the price is quite reasonable for the quality of their product. I would recommend 70 Shore-A material for both the lipped upper and flat lower front crossmember mounting pads (BMC Part # AHH 6204, AHH 6206, respectively; SuperFlex Part # SPF0015A, SPF0015, respectively). Click on this: http://www.racecar.co.uk/SuperFlex/
Steve S.

Thank Steve. It didn't look that hard but is great to be able to ask someone who has tackled the job just in case there are some things to watched out for.

Bruce
Bruce Mills

Are the polyurethane parts not available in North America?
Bruce Mills

Bruce,

A few years ago, the Superflex bushes used to be available in the US through the "car orphanage" in Arizon (I think) and for a little while "the Bhive" in South Carolina.

No one seems to carry them in the US anymore.

I used the superflex bushes on both the front and rear suspension of my car, a '73 B, as per Steve S.'s review some time ago. They are much better than the polyurethane bushes that I had used in the past on GM cars (ranging from the ease of fit to lack of squeaking).
Zach

Bruce,

I did exactly the same operation on my 64 last week!
After locking the back wheels, disconnecting the steering column and pulling out front wheels, I left the front member staying down onto 2 wood blocks in exactly the same position than onto the car and litfed up the nose with one hydraulic trolley jack( no engine in car, so easier ). Presumably you may need two jacks if engine still in place? It may be useful to use one of the bolts from upside to realign the chassis rail holes with those on the front member, to prevent boring manoeuvres from under the car.
I don't know exactly on a 74, but things must go in a similar way.
I hope that helps.
Regards.
Renou

Thanks All

The parts have been ordered.

Bruce
Bruce Mills

Don't you need to watch you don't let the front pair of bolts drop right through since they are inside the crossmember and you can't easily get in there to replace them? I seem to remember my crossmember has holes in it that you can put a rod or long screwdriver through to stop this happening.

I actually now have a whole CB front end spare. Will have to look on that one to see how this all works.

Simon


Simon Jansen

Interesting point Simon. I just took a look at the 74.5 front cross member. The holes are there as you mention but I am not sure what use they would be. Would you not have to pretty well remove the bolt to get the new pads in. The bolt goes through the pad.
However if I were to drop the coil spring I could reach into the cross member and control the bolt from there. I still would not have to totally drop the cross member.

Renou The engine is out. How did you deal with the front bolts?

Bruce
Bruce Mills

Bruce, you're right. I went and looked on my cross members and the little holes are too far up. You can't drop the bolt down enough to get the pad in. I think they are there so that you can assemble the cross member fully with the bolts in place and then lift the cross member up onto the car.

If you have the springs out you have no problem as you can reach inside to get to the bolts in place anyway as you say. I find the easiest way to do that is undo the top suspension bolt (the one that goes through the damper arms) with a jack under the spring pan. You have to have the front of the car up quite high. With the bolt removed just lower the jack to release the spring tension. With all the tension off I find you usually have to then push the pan down by hand to be able to pull the spring out (unless you have shorter springs).

If you do that make sure you don't stress the brake hoses as the swivel axle will be very free to move about without the top pin in place.

Simon
Simon Jansen

This thread was discussed between 26/01/2009 and 29/01/2009

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