Rear suspension dimensions

[GavinL]

I'm going to have to replace all the suspension mounting points on my saloon, the front ones are original and the floor has rotten around them, and the rear ones have been extensively bodged. I've made a jig to help locate them.

I'm also checking the dimensions, and the stated dimension for the front mounts is 107.59cm over the anchorage bolts. I've measured it as 106.5cm, with the bolts extending 1.25cm beyond the mount. I'm curious why they state the dimension over the bolts rather than the mounts, surely there is a possibility that different length mounting bolts could be fitted over time? Does anyone know the official dimension between the face of the mounts?

[philthehill]

The 107.59mm over the ends of the front anchorage bolts is taken from BMC Alignment Chart illustration R17.

The chart was drawn when only BMC parts were available so there was no requirement to query the measurement. Those parts were standard and usually made on a mechanised capstan lathe.

The only variance I have found so far in the rear front shackle pin between OE and aftermarket items is that the thread can now be UNF instead of BSF.

I would therefore fit the suspension mounts to the measurements as specified in the alignment chart.

Phil

[GavinL]

Phil, i agree the shackle pin dimensions of those available today are unlikely to be significantly different, which is why i am surprised the dimension on Vanessa is greater than that stated - 1092mm compared with 1076mm in the manual. All the evidence on the car is that the suspension hangers haven't been changed - the four locating rivets are still in place. They are also both in the same relative position in relation to the pressings in the floor, i.e. the outer edge of each mount lines up with the nearest pressing, and are as close to symmetrical as i can measure without being able to mark out the centre line of the car.

Has anyone else found the dimensions on their car significantly different from these stated in the manual?

Does anyone have any advice on how to find the centre line on a car on its side? I was going to try the middle of a threaded rod through the middle of the rear suspension mounts, and the middle of the crossmember as reference points, with a string between them?

Interestingly the rear suspension mounts, which have been heavily plated and bodged, do measure approximately correctly - 1085mm compared with 1089mm in the manual - 0.37% different, so should be OK to use as a reference point.

I've also checked the distance between front and rear mounts, which appears to be spot on at 1102mm ( not stated in the manual but a simple bit of trig based on the dimensions given).

All thoughts welcome.

[taupe]

When i did my traveller I struggled with the same mounting point dimensions given in the manual ....one of the dimensions I measured was between the inner faces of the front leaf spring mount brackets without the pin plates in place.. it was 37 5/8" approx.....What does yours measure across at that point?

I recall that the leaf springs worked out pretty close to 40" 'centres' across the car width allowing for some slight variance due to the rubber mounts once assembled.

If your mount brackets are still riveted then I would trust those existing points as accurate and replicate the existing positions doing one side at a time.

Taupe

[GavinL]

Thanks Taupe, i'll measure that dimension tonight and see how it compares. I think I'll also remount the springs and swing the car horizontal and check if they are parallel on the existing mounting positions.

[GavinL]

So I measured the distance between the inner faces of the front Spring hangers which is 37 11/16" so almost identical to Taupe's measurement. I also rehung the springs and measured the width across the springs, which measured 1050 to the outside of the springs along their entire length, so they are parallel. So I'll be replacing the hangers to match the existing hangers positions.

This does however raise the question if I installed the hangers to the dimensions in the manual the springs wouldn't be parallel.

[philthehill]

Some leaf spring fitments are not parallel and the distance apart at the front is less than that at the rear.
I will try and measure my rear spring front hanger mounts which are original and have not been welded or plated.

[GavinL]

Below is a summary of the dimensions i measured. It would be interesting to know what others have measured these dimensions to be.

[philthehill]

Dimensions as promised:-

Distance between spring centres at the front of the spring....................................................39.75"........(1009.65mm).

Distance between inside faces of the spring hanger at the extreme front of the hanger...........37.562".....(954.0mm).

To reiterate - the Minor 1000 that the dimensions have been taken from is a 1958 two door saloon which has the original floor and spring hangers and has not been welded or messed about with regards to the floor pan in the area around the rear spring front hanger.

I hope that you find those measurements helpful.

Phil

[GavinL]

Phil,

Many thanks, very useful. So this would appear to confirm that the front hangers should be approximately 954mm ( 37 9/16" ) apart. I measured the dimension as slightly wider, but i'm sure you measured it far more accurately than me , and the imperial dimension makes sense.

[GavinL]

just revisiting this thread, I've realised that the possible reason for the difference in my measurement G and the dimension D on the diagram may be contributed to by the complete absence of any evidence of the shipping bracket on my car, which i assume adds to this overall dimension? Can someone with a shipping bracket confirm the thickness of it please? i assume this is also required to reinforce the rear hanger, so i may make my own, without the towing eye dirt trap.

Edit - just found a post from Taupe saying that the it can be replaced by a 2mm plate - is it really this thin, bearing in mind it is doubles as a shipping bracket as well as reinforcing plate?

[Peted7202]

1958 2 door. Its on a rollover jig so good access for measurements.

My measurement from the front to rear body spring hanger hole centres is 1086. Significantly different to the manual.

The trig calculation for the front hanger and rear hanger bottom shackle hole centre is 1080 (confirmed by measurement). The shackle has 60mm hole centres.

Both leaf spring mounting eye centres are 1080mm.

Looking at the manual R17 the front edge of the front hangers should align with the cross tunnel joint.

Observations/Questions
The significantly different front to rear body spring hanger hole centres?
The front hanger to rear hanger bottom shackle hole centre matches the spring eye centres. This would mean a neutral load when refitted (off the ground). Should this be like this?

Any thoughts/advice?

[kevin s]

When I did ours I took loads of measurements before I cut it up, the original spring hangers were all over the place one was 15mm further forward than the other, I forwent originality and put new ones in the right place according to the manual !

[Peted7202]

Thanks Kevin. My left hand is 15mm different to the right hand between the front and rear hanger hole centres.
Does anyone have a picture of the rivets mentioned in this thread?

[taupe]

Yes here are the rearmost ones and a pic showing the four on each mount with temporary 1/4" screws in....

Spring hanger Rivets.jpg (139.15 KiB) Viewed 2287 times

spring hanger etc 032.jpg (838.78 KiB) Viewed 2287 times

Taupe

[Peted7202]

Thanks taupe. Did you fit rivets/bolts as a permanent fastening?

[taupe]

Yes 1/4" steel rivets heated to cherry red one end then set home with a rivet set tool

Taupe