Frontend geometry..upper suspension - advice?

[Bluesman]

Hi guys - I am preparing for a RHS chassis leg replacement. While preparing things and bracing myself, I found a difference in clearance where the suspension arm enters the engine room sides (terminology?).

Have a look:

http://homeweb.mah.se/~lurija/susp_LH.jpg

http://homeweb.mah.se/~lurija/susp_RH.jpg

Strange, innit? I have to add that the bulkhead section where the dampeners are mounted is absolutely solid, and the dampeners seem untouched by humans. The metal on the RHS of engine compartment looks fine to me, no visible repairs or damage from any impact or so.

So...can the upper suspension arm have become bent due to a crash?
I don´t believe it can, it looks like cast iron and would have cracked, not become bent. Besides...bent *forward* is very unlikey.

Other causes? Could it be due to the lower suspension almost having collapsed due to rot in the chassis leg? Or is it a case of bad upper suspension components?

Most important: how do I go about to diagnosticize (and cure) this anomaly?

Cheers /Richard

[chickenjohn]

Yes, it could very well be the rotten suspension leg that is causing this. Things will hopefully look better with the new leg in.

[MoggyTech]

Measure from the bulkhead beam where the damper is bolted to, to the front of the inner wing slot where the damper arm passes through. If measurements differ, r/h inner wing has been repaired at some point.

Measure Kingpin Inclination on each side (in degrees). If different r/h suspension geometry is out due to worn bushes and or chassis leg problem.

[Peetee]

Also check the r/h damper bolts are fully in. They look very worn - the previous owner might not have been able to tighten them fully.

[Bluesman]

Damper bolts - the ones that attach the damper to the boxed section/firewall? OK, I´ll have a look and also take some measurements later today. Thanks for the pointers so far.

/R

[rayofleamington]

Don't forget to measure the dampers as well as the bodywork.

[Bluesman]

Ray - what exactly should I measure up, please?

Idea: Firewall (boxed section where dampers are bolted) to foremost wing fastening nut, bulkhead to vertical inner wing slot, diagonal distance from innermost corner of boxed section (where it meets inner wing) to opposite side foremost wing nut? Things like that should give me an idea of where to look for deformation when compared LHS/RHS.

Perhaps you mean measuring the damper itself - how far out is the extension arm from the damper body, things like that?
/R

[rayofleamington]

Perhaps you mean measuring the damper itself - how far out is the extension arm from the damper body,

Yes - just in case you've got a non standard damper on there!

The hole in the inner wing for the damper arm is so close to the cross member and the 2 parts are directly connected to each other, Therefore it would be difficult to get this much distortion (unless it was obviously badly bent) - therefore I'd say the damper itself could be the issue. Measuring will give you an answer one way or another!

[Bluesman]

Well, looks like I have something else bothering me. The dampers are identical, both screwed in tightly and look untouched. The suspension arms are OK, and do not seem bent/cracked.

What is NOT identical is the distance between the damper axle center and the nearest point of the inner wing, measured horizontally. The difference is about 20mm. So either I have distorted inner wings (no visible damage) or a car that is assymmetrical (not likely).

If the RHS inner wing is bent/dented closer to the damper, the vertical slot would end up closer to the suspension arm "knee", and the distance/free play between slot and "knee" would shrink automatically. So..is the RHS inner wing too close?

To confirm this, I made some measurements from what I believe is the centerline of the car and out to the foremost wing mount nuts, and from the centreline to the end of the thread of the bumper mounts. Both measurements give longer distances from the center > LHS points. My suspicion is that this car once was the victim of a RHS/front-end accident that has skewed the front end - inner wings and all - just a bit towards the LHS. The hood and the wings still seem a good enough fit, but that could have been pulled reasonably straight by any amateur with a chain hoist. The inner wings are a different pie, so to speak.

This is bad news, if it´s true, especially if the chassis is bent too. I don´t have the tools to draw the frontend straight. Once the engine is out, I will cross-measure the fixed points that I can trust and compare against the measurements in the workshop manual. I may have missed the centerline, and my measuring skills/tools are crude, but...

Dang. Keep your fingers crossed, OK? I can live with a skewed engine room, but defintely not with a skewed chassis.

/R

[MoggyTech]

It does sound as though the car has had a side frontal impact that has distorted the front clip. Most likely both chassis legs will have been pushed to one side. As you are replacing one chassis leg, when you get the old leg out, the other leg can be heated and made true with a power ram. The other alternative, is to replace both chassis legs, using the datum references in the BMC manual.

[Bluesman]

GHAAA. Doomsday is getting closer..I thought I just had my share of bad stuff to last me a year or so (buried yet another much loved cat yesterday)

Once I have her propped up on blocks again, engine out, I will check for bent chassis legs. If they are, there is a spare parts car for sale at this end.

Grrrr..../R

[bmcecosse]

It will be fine! Once you get the new chassis leg in place - just square it all up before you finally weld everything. It's been so badly rotted that what's left will easily distort slightly. It's a 40 year old Morris Minor you're working on - not a F1 car!!

[DaveC]

For what its worth, when I changed my front dampers a couple of weeks ago I found I had 2 sets of (4) holes to fix the damper to the crossmember. (I remember thinking, 'must use the same holes'). I don't suppose that someone has fitted the damper to the wrong set in the past? They were about 20mm apart horizontally.
Just a thought...

[bmcecosse]

I've asked many a time what these extra holes are for - no-one seems to know!

[DaveC]

Maybe a differrent type\make of damper perhaps? The unused sets are lower and nearer the centre of the car. Certainly would mess the geometry about if the wrong set were accidentally used on one side, I din't know if the unit would fit though..

[bmcecosse]

That was my assumption - but never seen a different set used, nor has anyone confirmed such a thing. And although the Wolseley1500 is the same chassis and uses the same swivel uprights - it has a very different top damper mounting.

[tortron]

This is an old thread, but the only with a similar issue to mine

I am replacing the original 65 year old front dampers on my minor and have a set of recon ones

There however is an issue with one of the arms being a different casting. it is a different profile and its slightly different shape is obvious when comparing against the others

With all dampers flat on their backs on the bench and measuring to the bottom edge of the pin hole at the end of the arm the odd one out measures 7cm. All others measure 6.5 cm

this difference appears to affect the entire arm, as the front fouls on the inner wing window. Checking against the originals i have approx 5mm clearance, and the other replacement is the same. which seems to rule out any issue with the bodywork

I am returning the odd one to be swapped for one that measures the same as the others.

Perhaps this was a similar issue

[RobThomas]

Both of my MM-series cars have similar differences in clearance. Both cars have camber and caster within tolerances, although hard to do with original MM suspension arms that don't have flat sides to put a level onto. The other dimension to check would be hub centres between the front and the back wheels on both sides to see if the legs are set with the same distance and the same caster angle. I would have thought that if 3.4mm equals 1 degree of camber then 5mm at the top arm would affect the caster enough to be measurable?

When I had my big crash about 12 years ago the top arm of the damper was bent through nearly 90 degrees but the bulkhead and the bolts were undamaged. Soft material for the top arm?

[tortron]

In this case it would mean that the arm had been bent forward. Possible but unlikely.
In my case at least the car is straight and solid, and measuring of all the dampers puts the difference solely in the odd arm

The casting is definitely different, with a different profile where the arm mounts the shock shaft.

[bmcecosse]

Quite right to send it back - and at no cost to you!