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MG MGB GT V8 Factory Originals Technical - Factory V8 Front suspension failure
|Thought I'd share this with you-and then you can go and check your cars suspension,I have to admit to inheriting and driving my 73 V8 with the n/side caliper sticking, most of the braking force going through o/side wheel, Driving home from working nights, thank goodness roads empty- I braked for a junction at approx 15 mph. o/s front suspension lower arms snapped, causing wheel to tuck in somewhat!I was dog tired so drove car very very slowly last half a mile, wheel held on by track control arm and top shock mounting only.Checked damage-o/side lower arms had snapped around bolt holes for lower spring pan. evidence of rust suggests this was happening for quite a while, n/side arms no problems found at all. |
When I went to my MG parts company-(Summit)they had not heard of this happening before, its likely my car had received some trauma during its 29year life to cause this, but just in case I suggest you give your suspension the once over, P.S I had to get the rack mounting brackets welded as well,similar rusted cracks around the offside again
|The exact same thing happened to my B a while back. While up on my lift I was looking underneath and shocked to find only 1 or 2 bolts holding the spring pans in place- barely. Since I needed the car that moment, I simply welded it permantly on. Good advise to check these parts.|
You may have created more of a problem in the long run by welding the spring pan in place. With it welded, you will not be able to relieve the spring tension and disassemble the rest of the front suspension components. Your only option will be to place a jack underneath the lower control arms, then remove the control arm pivot to crossmember bolts and lower the jack. Changing the lower control arm bushings will be impossible also.
I would make sure that the bolts used on the lower spring pan are the correct grade, at least Grade 5. Many of the problems with suspension failures can be traced to incorrect hardware.
|It's not uncommon for this to happen, rust can cause this problem, but also lack of maintenance on the lower grease fitting.|
I have seen MG's with frozen lower pins, when this occurs the bolt rotates on the lower "A" And it get the elongation treatment. The first sign is more camber in one side.
This area of the lower A is not very thick and is one of the weak points on the B's suspension and itís also a very soft metal, the reason for this is so that in case of extreme use it will bent instead of braking.
Welding the bottom pan to the frame is a way to stiffen the front suspension when a tube shock is installed in the car. The welding of the pan reduces the twisting that occurs with the tube shock mounted outwards of the thin A frame.
The down side is as Paul Kile mention, it makes it difficult to work with, especially installation and forget the lower bushings.
|Just changed my A-arms and inner bushes. I have been getting a slight 'clunk' under braking and a 'boing' when turning from lock-to-lock, and having seen pictures of someone elses ovalled A-arms and lower pivot bolt worn half way through thought I had better have a look at mine. In fact there was no wear even though the bolt on the RH side (which was where the 'boing' seemed to be coming from) turned easily before I had started undoing the nut.|
In the past I have always removed the pivot bolt and lowered/raised the spring pan and A-arms complete to remove/replace the spring, but this time I thought I would try it by disconnecting the spring pan from the A-arms first as many seem to recommend. What a Royal pain in the ar*e! For a start the anti-roll bar drop-link was seized in the A-arm and pan so I had to remove the spring the old way. But I persevered and tried to re-install the spring that way. Why anyone bothers with this I do not know. You have to jack up the pan, and unless you can do it so all four bolt holes line up at the same time you have to insert one bolt at a time, try and get the washer and nut on with the jack in the way, then jack a bit more to get the next bolt in, which twists the first in its hole and damages the threads. All the while with an unsecured spring under significant tension a couple of inches away from your face. Sod that for a game of soldiers, on the second side I reverted to assembling the pan and A-arms first and did it in a fraction of the time.
|Paul, I haven't yet taken my V8 apart, but is it not v similar to midget in that you can use 2 extra-long bolts through diagonally opposite holes as spring compressors until two normal bolts can be done up finger tight. Then remove the long ones and swap for the other 2 regular ones. I did this on a mIdget and it worked OK. It was still a pa1n in the @ss though, and I've reverted to the jack method.....|
|Yes, unless the engine and fenders were off the car when you wanted to rebuild the front end. Then, all jacking up under the spring pan does is to raise up that side of the car off the jack stand! Had to buy and modify an expensive spring compressor to be short enough to compress a B spring! Can't wait to try the jack method next time, and I'm with Paul as to installing the pan, A-arms, and spring all as a unit; very neat package that way.|
This thread was discussed between 23/02/2002 and 01/03/2002
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