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MG MGA - Jacking an MGA

To my surprise when flicking through the Haynes Workshop Manual for all MGA models recently in the Jacking section it shows the normally recommended spring pan and rear axle jacking positions but states “never position the jack beneath the chassis side members”. Referring then to a similar section of the MG Workshop Manual for the Twin Cam it also states “the car must not be jacked under the frame side members”.
Presumably this would be referring to a single point bottle jack or similar placed under the side members which might unduly stress/bend the chassis?
I only ask because I sometimes use a hydraulic scissor jack which has front and rear lifting points on each side under the side chassis members, each point being under the straight piece of side chasisis, roughly from a position behind the front wheel arches to the middle of the doors, a length of 30/36”.
Anyone? Does that sound damaging to an MGA?
Bruce.
Bruce Mayo

Bruce,
whenever I have been to Bob Wests or to his ex-restorer James Horner's new workshop at Common Lane Restorations, they use a 2-post lift when they raise the car to work on it.

They have both always positioned the front pads of the lift beneath the chassis rail behind the front wheel, with the rear pads fitting beneath the actual rear spring just behind the spring hanger at the forward end of the spring.

James says that this gives the best balance on the car lift with the weight being distributed more evenly and safely.

I suppose that the rear spring already takes the weight of the car and so it should certainly be strong enough to do the job safely.

I have always used a trolley jack to raise the rear of the car, I use a wooden pad on the jack with a hole cut out to prevent pressure on the axles drain plug. Then I quickly fit axle stands under the centre of the spring plate, using a wooden pad to protect the ends of the U-bolts.

I understand that the axle casing may not be the best place to use to jack up the rear of the car but I make certain that the weight goes onto the axle stands under the spring plates as quickly as possible.

I am similarly open to suggestions on this matter.

Cheers
Colyn

Colyn Firth

I have been using my 4 point hydraulic lift on the chassis rails for years. No problem.

Steve
Steve Gyles

Jacking on the ends of the side chassis rail should be fine, I'm wondering if they're meaning not to jack on the body/sill section which of course would be a disaster
William Revit

Take a look at this - on Barneys site www.mgaguru.com/mgtech/care/cf114




Graham V

Graham
Ouch!! That doesn’t look good at all. Thanks for the replies guys.
Bruce.
Bruce Mayo

That looks fine to me. The tube on the top of a scissor lift jack has a cut out slot in the top that allows the tube to locate either side of the chassis welded joint flange. The only issue I have is that it is manually operated! The 12v motorized unit is the way to go.
Mike
Mike Ellsmore

It is just a question of how much weight is supported by how little jack to chassis rail contact. A jack with a pad that distributes the weight = no problem. A jack with a single 1" pad can result in a dent in the chassis rail.

I always use a floor jack under the rear and under the front crossmember, but when you are 'in the field' and have a flat, make sure that the jack you carry has a large enough pad on the contact point.
Bill Spohn

This is no big deal, been doing it for decades. The picture above is from my frequent autocrossing days in the mid to late 90's. I knew I wouldn't have to go back very far to find a more recent picture. The first one is from April 30, 2021 while changing a clutch hydraulic pipe. The second one March 12, 2021 when I pulled my propshaft to change a U-joint. I also do it any time I change the engine or gearbox oil and lube the propshaft and hand brake cable (if no hoist is handy). Just be sure the frame is solid, not rotted out.

All due precautions when using a screw jack or bottle jack. Those things have much smaller base than a trolley jack, much easier to tip over, so you need to be more careful with parking brake and blocking the tires so it can't roll.






Barney Gaylord

This thread was discussed between 23/05/2021 and 15/06/2021

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