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MG MGA - b front end on an A

Hello Fellow Enthusiasts,
i have a 79 b i am not sure what i am going to do with just yet. will the front end, spindles and brakes fit my 59 A?

mark
Mark Youden

There should be information on this in the archives. In short, the B suspension will work on the A. You will need to fit B brake hoses and use spacers on either side of the upper trunion in the A shock.
Bill Young

Another route to take is using the B damper too. Just slot each hole 1/16". I converted a '58 to a '72B brake system for the benefit of a separate circuits and better calipers. $40 each side for original Lockheed with a lifetime warranty. Hubs had to be switched as well. Fitting the pedal box is turning out to be an engineering feat.
Scott

anyone tried using the B arms on the A shock? Would thin eliminate the need for the specers? Are they longer/shorter/different than the A? Since the dampening pistons are inboard, rather than the outside like the B, there should beno clearance issues (but the MGA's in California and I'm in MI)
greg fast

I ressurected this thread to re-ask the question that Greg Fast asked about the possiblitity of swapping shock levers betweeen the A and B shocks. Also, there is a set of MGA shocks on eBay right now that appears to have the arms flipped 180 degrees. Here is the URL for one of the listings:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7938696838&category=33590&sspagename=WDVW

The configuration of these shocks raises another variation of the question, can the MGB arms be similarly flipped and the correct shock action maintained? If I understand the technical threads correctly, either of these approaches would take care of the assymetric mounting hole problem with using the MGB shocks with an MGA frame.

Not to inject a morbid note, but I am toying with the idea of switching to a MBB front end set up because years ago an acquaintance of mine died when his Spriget swivel pin broke and his car flipped. The MGB king pin arrangement is stronger and I would prefer to make the conversion as clean as possible without using spacers or hogging out the mounting holes.

Steve
Steve Brandt

I'm not in favor of slotting the MGB shocks. We mount the MGB arms on MGA shocks at my shop. Actually, we have them rebuilt by World Wide in Wisconsin and they set them up this way for us.

I agree with Steve that the MGB kingpin is much better than the MGA. We regularly see bent MGA kingpins and have seen them fail. I've only seen MGB ones fail due to lack of grease in the wheel bearings.

Here are pictures comparing MGA kingpins/drum brakes with MGB kingpins/disk brakes:
http://www.eclecticmotorworks.com/mgbsusp.html

--Carl
Carl Heideman

Oh, the shock on eBay is not an MGA shock. I believe it is for a T-type, but an not sure.

--Carl
Carl Heideman

I found that a 1/2" shaft collar fitted on either side of the B upper trunion exactly filled the space in the A shock arms. If you have good shocks on the A this is a clean and easy way to fit the B components.
Bill Young

Carl-

Interested in the failures of the MGA kingpins. Especially location of the failure and cause.

i'm usinging an MGA lower trunnuion with a kinpin made from 8620 steel, machined to MGB kinping dimensions, the flame hardened and ground to size. Doing this to lower an MGB race car.

Since the kingping and swivel axle aren't locked together, I THINK this should be adequate, but I've heard of MGA 'kingpin failure' but never spoken to anyone whose seen a failed kingpin and could answer this question.

Course, living in California may be the reason- it's not like it's a hostile envirornment.

And do plan on using MGB setup on the wife's MGA

greg fast

And Carl-

Thaanks for the url- I was glad to see that the idea wasn't too stupid- I couldn't believe that no one had tried this out, glad to see someone had
greg fast

The most common problem we see with MGA kingpins is that they bend--very common.

We recently saw a Twin Cam race car where the kingpin broke in the threaded area just above the lower trunion.

We had another one where the threaded part of the kingpin pulled loose from the trunion--but this was a very rusty kingpin/trunion.

The most common problems are that the lower bolt eggs out the A-arm and/or the A-arm "slices" through the lower bolt. This happens as frequently on MGBs, and in either case is because of lack of grease and siezed lower fulcrum.

So the short answer is that MGA kingpins are likely to bend but not fail catastrophicly unless they are not greased. MGB kingpins do not bend.

--Carl
Carl Heideman

good news, thanks Carl

I have the kingpin section that the swivel rides on turned from 8620 to MGB dimensions. Bearing surfaces were flame hardened and precision ground to diameter.

Can you tell me where the MGA kingpins generally bend? I'm not that familiar w. the details of the MGA kingpin- I know the threaded section moves in the lower trunion when the swivel axle turns, but the length above the threaded section- just not ver familiar with the diametral steps and the upper trunion area
greg fast

This thread was discussed between 30/11/2004 and 08/12/2004

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.