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Front subframe clearance
https://ausmini.com/forums/viewtopic.php?f=2&t=98313		 Page 1 of 1
Author:  rocky&bullwinkle [ Fri Mar 01, 2019 6:10 pm ]
Post subject:  Front subframe clearance
Hi,
New to this forum after getting my hands on a 1963 850 with sliding windows. It's a complete car that's been in storage since 1987 and in pretty good nick but it has had a few knocks in it's life and I'm doing a full resto on it.
Many years ago, it had a good knock on the passenger side and when I pulled the floor vinyl up, I noticed that the subframe looked to have been pushed back as the floor where the rear of the subframe bolts onto was bent. I checked the wheelbase and found the passenger side is about 15mm shorter than the drivers side. After taking out the subframe, I found that the passenger side tower had been bent. Can't see any damage at all inside the engine bay on the firewall where the tower bolts are so I reckon the body itself it ok. Also measured from the rear subframe and things are equal on both sides.
I've now got hold of a good 2nd hand subframe that I took of a van that I think was made in NZ going by the compliance plate and this has a few differences to the old one. I've noticed 2 things straight away - the towers have a reinforcing plate welded inside the tower just above the lower control arm bush area where the lower control arm bolts in. The plates look like they've been there from the factory. The 2nd thing is that the lower control arms themselves have tapered bushes whereas mine has straight ones. From my understanding, the tapered bushes come in sometime after 1966??. I'm going to use my old arms anyway so no dramas there.
I've fitted the new subframe to the car to make sure it fits ok before I reco everything and it does go in but the frame itself now sits up hard against the firewall whereas the old one had about 10mm clearance between the centre section and the firewall. There used to be 4 bits of packing material between the old subframe and the firewall.
Pics attached to help explain what I mean.

What I'm asking is "Is this ok to not have any clearance or do I need to try and get some thin packing inbetween the firewall".

Will the subframe move and squeak against the firewall or is everything all going to be held together and all move as one bit?

There is also a difference in the gaps behind the towers and the firewall on either side. Is this normal?

Will I be ok to use the new subframe or should I get one from an older model so it's exactly the same as the old one?

Given my old subframe was out of whack, I'm not sure what's normal.

Thanks in advance for any help.

Cheers, Rocky
Author:  1071 S [ Fri Mar 01, 2019 6:24 pm ]
Post subject:  Re: Front subframe clearance
Get the body level and measure the reference points to make sure the front subframe is square and the correct distance from the rear.

There's a diagram in the Factory manual that gives the distances/measurements.

Cheers, Ian
Author:  rocky&bullwinkle [ Fri Mar 01, 2019 6:53 pm ]
Post subject:  Re: Front subframe clearance
Thanks Ian. I've got a factory manual and have checked the wheelbase with the new subframe and it's pretty close now. What makes things a bit hard at this stage to check everything is that the suspension components are all well worn and lots of movement in them. The drivers side rear wheel has a fair bit of toe in as well so hard to get a centre for that one. I know the measurements from the holes in the floor where the rear of the front subframe bolts up to the rear subframe mounts are the same on both sides but I'll work out what the actual distance should be and check that.
Body is sitting up higher at the front at the moment for access but will level it out tomorrow and measure up.

Cheers, Rocky
Author:  p7676 [ Fri Mar 01, 2019 8:49 pm ]
Post subject:  Re: Front subframe clearance
I would jack the car up ,remove the door rubbers at the bottom ,get a length of square tube place tube on top of flanges which hold the rubbers on ,then use a spirit level on the tube .Level the car with stands and packers. At the front of the subframe level a length of tube on the floor. Use this tube for your vertical datum measurements, height at the front is the same both sides. Then check length measurements and a diagonal measurement. It is better to take measurements off a good undamaged body. I can get the front spot on although it is difficult to explain how the repairs are done. You usually need some plates bolted to a concrete floor to hold the car, Most minis are higher one side which means there is a twist in the body. The subframe is easy to check when it is out of the car. I used to repair them.
Allen
Author:  rocky&bullwinkle [ Sat Mar 02, 2019 6:55 am ]
Post subject:  Re: Front subframe clearance
Thanks for the good info Allen. Looks like a day in the shed getting it set up and measured.

I've been told that all the subframes (dry) are the same - is this correct? When I pull the 'new' one out, I'm going to check a few measurements against the old one just out of interest. Visually, they look the same (except for the extra bracing inside the tower).

Rocky
Author:  9YaTaH [ Sat Mar 02, 2019 7:56 am ]
Post subject:  Re: Front subframe clearance
p7676 wrote:
Most minis are higher one side which means there is a twist in the body. The subframe is easy to check when it is out of the car. I used to repair them.
Allen


Interesting...twisted, as constructed on the assembly line? (variations in panel sizes and mating/welding during assembly?) or does the engines torque reaction twist the bodies?
Author:  p7676 [ Sat Mar 02, 2019 3:57 pm ]
Post subject:  Re: Front subframe clearance
wear and tear in the bodies and subframes over a long time. from new about 3mm higher one side, I have noticed about 8mm variation in height as I check before I replace rusted guards and front apron. Also the subframe needs to be held down one side and jack up the other. I used to use 3 gunsight gauges which go across the body in 3 places. Now with a flat steel bed like the Caroliner it is easy to measure vertical datums ,lengths and width. Problem is easy to fix, My CS is within 1mm tolerance new cars are plus or minus 1 or 2 mm tolerance .Maybe some are perfect I have measured different makes of cars.
Author:  9YaTaH [ Sun Mar 03, 2019 7:55 am ]
Post subject:  Re: Front subframe clearance
p7676 wrote:
wear and tear in the bodies and subframes over a long time. from new about 3mm higher one side, I have noticed about 8mm variation in height as I check before I replace rusted guards and front apron. Also the subframe needs to be held down one side and jack up the other. I used to use 3 gunsight gauges which go across the body in 3 places. Now with a flat steel bed like the Caroliner it is easy to measure vertical datums ,lengths and width. Problem is easy to fix, My CS is within 1mm tolerance new cars are plus or minus 1 or 2 mm tolerance .Maybe some are perfect I have measured different makes of cars.


Interesting...with all the other variables that effect handling like sub-frame and suspension alignment and driver weight etc must be good to know you have at least started with a straight body :D
Author:  AEG163job [ Sun Mar 03, 2019 8:09 pm ]
Post subject:  Re: Front subframe clearance
As Bill Williams famously said - if driver weight is a problem, go on a diet.
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