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MG Midget and Sprite Technical - Not an April fool

Chaps

Disaster struck today....nearing the end of the rebuild of the 71, pushed it out onto the drive to check mixture. Brakes not working yet, handbrake also u/s at present. Engine off, choke fully out, check all electrics, ignition on, turn key, fires up - except it is in gear! I go flying away - heading towards the road entrance with no brakes, so I turn and hit a low wall instead at about 10 mph. Not much time to do anything else......

Result - one very crushed front logitudinal/chassis - see pics - the 12 inches or so protruding forward from the front crossmember, tracking totally askew, front panel totalled. Fortunately the glass fibre bonnet was not on - so some saving grace there....

However, the front part of the chassis is a problem. The rear portion just in front of the cross memeber is totally deformed, and not salvageable, and the upright which I think is the radiator support is also damaged.

Questions then

Is this is a cut off, weld, and replace the damaged bits? - If so, then where for parts please? Rest of chassis looks OK at first glance, but I will check. Obviuosly I only need the front 12 inches or so of the chassis longitudinal in front of the cross member, and possibly the vertical for the radiator support.

It has Frontline set up at the the front, tracking well out, anything else I should check here?


Needless to say I need a few drams!


Oggers

...and to answer my own question, Moss appears to have a front chassis leg - item 4, and a vertical item 7.

Seems feasible....
Oggers

Hi. Sorry to see your distress. It is not unusual on race cars to reweld part or all of the H frame. All is not lost.Good luck
s page

SP...No indeed, and as the car has a 2.0 Zetec up front and a host of other "racing" mods, your comment seems appropriate!
Oggers

Bad luck Oggers. At least the damage is confined to your car,
And, your pride!

But if it has only damaged the chassis leg forward of the cross member (Moss, item 4) then it is and easy job to cut off the old one and weld on a new piece. That piece doesn't take full suspension loading, but positioning and welding does need to be accurate and strong as it supports the anti-roll bar which does take quite a lot of force. The upright (part 7) supports the rad and the easiest way to align that is to bolt the rad to it and add the inner wing stay before welding, to make sure it is vertical and at the right height. Be particularly aware of the fan clearance from the back of the radiator.

But before diving in to repair, do check thoroughly for any signs of deformation further back, and to the inner wishbone mounting points which can be vuldnerable to transferred impact damage. Good luck!
GuyW

Having just said that if the damage were confined to to the forward pointing front part of the chassis leg (item 4) I have now seen your second photo - why start 2 threads on the same issue?

Anyway, although the photo angle is a bit obsured it looks like the cross member between the chassis rails has distorted or folded which is much more serious. It means that the two main chassis rails are no longer parallel and very likely one has also distorted upwards which will put the whole front suspension out.

If that is the case you could be looking at a new front "H frame" sub-chassis (Moss item 1 ) particularly as it is evident that there is some significant rusting of the chassis rails anyway as can be seen in the other chassis extension. If not a complete, and very expensive, H frame then it still looks like there is some serious straightening and re-jigging needed.

Hopefully what I am looking at in that photo isn't the cross member folded and kinked like that?
GuyW

Guy

Once again, many thanks. Your first post makes complete sense. Just taken another look, and I don't think the cross member is deformed. Cannot be 100% without looking underneath - but the cross member looks perpendicular enough between the frames. Looking at the second photo, I think the wavy deformed bit is the original metal on the leg - the 1" or so section between the cross member and the vertical.

Having a clam shell fibreglass bonnet which hinges from brackets at the end of the leg doesn't help matters either....

Garage job I think.......
Oggers

These were the bits in your second photo that I thought were the top and bottom flanges of the front cross member - and if they are, then they look heavily distorted as if the main section of the off-side front chassis leg has buckled inwards at that point. But maybe I am looking at it wrongly?


GuyW

Guy - thanks for that. I see what you are driving at - or not in my case! The top arrow points to the thin plate which comes forward under the radiator - definitely distorted, but not the top cross member flange in any event. This is hidden by that plate. The bottom arrow is indeed the flange, but the distortion is somewhat exaggerated in the pic - I think! Does not seem too bad....

I will order two legs and two verticals from Mr Moss and leave it to my local trusty mechanic, who unlike me, can undertake a decent weld.

All a bit of a blow. I was probably only days away from driving the thing....
Oggers

Sorry for your accident, hard though it is think at least only bits of metal have been damaged and not you or anyone else.

Just a suggestion, take it or leave it as just that - possibly better to get the person who's going to do the welding or full repair to have a look at the car as it is before ordering any parts. Usually a keen experienced eye and perhaps some measuring are very useful in these situations.
Nigel Atkins

I like your plan for this repair

Just remember to emphise that the H rail is not flat but has an upward curve

Iv e heard stories of those not familiar with sprdgets seeing the curve and thinking it's bent then level it on a frame machine.... not a good day


Prop
1 Paper

Prop is right, but the upsweep is achieved by a 3 degree upward bend in each main chassis rail, immediately behind the rear of the two inner wishbone pivot brackets. So the "horns" which you are replacing actually continue the same trajectory line of the chassis frame where they fix,

The other thing to be aware of is that when the upright stanchions are welded on, they must be fitted so that there is about a 3/16" - 1/4" gap at the bottom, as can be seen in your second photo. This is needed to allow water and road dirt to drain out, otherwise the side of the chassis rail will rust out.


GuyW

Prop and Guy, you have removed a long-held worry of mine. Years ago when I did the first front-end rebuild I found that the cross-member that carries the steering rack had been bent back, presumably accident damage. I got this repaired, and then noticed that the chassis rails were not straight. I have worried ever since that this was also accident damage, but tried to forget about it. I can now do so with a clear conscience.

Les
L B Rose

Les,

Don't blame me for your peace of mind, the BBS IS RICH with great info and so many people willing to provide what they know to help everyone else

It's a great community

Prop
1 Paper

This thread was discussed between 01/04/2018 and 03/04/2018

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