New springs alter TC rear axle location.

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Ray White
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New springs alter TC rear axle location.

Post by Ray White » Mon Nov 25, 2019 4:50 pm

I fitted new springs to the rear of my TC and it has resulted in the axle being moved back by about half an inch. This has meant the check straps no longer line up with the holes in the chassis but more importantly I can see prop shaft problems ahead. One option would be to add a spacer. An alternative option I considered would be to make new spring bolt reinforcing plates ( I think that is what they are called?) with the rivet moved along by 1/2"?

What would you guys suggest is the best way round?

There may also be adjustments needed to the hand brake cables and hydraulic brake lines; not to mention the wheels not being central in their arches.

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Steve Simmons
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Re: New springs alter TC rear axle location.

Post by Steve Simmons » Mon Nov 25, 2019 5:14 pm

If the springs aren't made correctly then I would return them. They should be identical to the originals. See this link for specs on the factory springs:
http://www.tcmotoringguild.org/techinfo ... g-data.jpg
1949 TC8975 / XPAG 9609
1949 TC9849 EXU / XPAG 10507
http://www.mgnuts.com

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Duncan M
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Re: New springs alter TC rear axle location.

Post by Duncan M » Mon Nov 25, 2019 8:14 pm

Where you get those bum springs? Something wrong with your driveshaft?

Ray White
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Re: New springs alter TC rear axle location.

Post by Ray White » Tue Nov 26, 2019 1:38 am

Having spent time squaring off and chamfering the ends of the leaves and fitting new shackles and bushes etc., I am reluctant to return them. What if the replacement springs are just the same?

Quality control has become a problem in modern Britain. It is very sad because we were once renowned for being the best in the World in just about everything.

I think the easiest thing to do will be to modify the plate so the rivet is moved along and locates the leaves in the right place.; a spacer on the prop would only resolve one of the problems.

I have a brand new prop shaft that was made specifically to go with a 5 speed box. They have not been fitted yet...
Last edited by Ray White on Tue Nov 26, 2019 1:43 am, edited 1 time in total.

SteveW
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Re: New springs alter TC rear axle location.

Post by SteveW » Tue Nov 26, 2019 1:43 am

Hi Ray,

Do you have a copy of the Brown Book ("Workshop and Tuning Manual by W.E. Blower). If so, that has a diagram that shows the correct dimensions of the springs and the locating dimples. With the spring under load so that it's flat, the dimple on the main leaf is 18" from the end with the large eye hole and 18 1/2" from the end with the smaller eye hole. It is that dimple that locates the rear axle position fore and aft. I need to find time to come and see you as you are only just down the road from me. I could bring my copy of the Brown Book with me.

Steve

Ray White
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Re: New springs alter TC rear axle location.

Post by Ray White » Tue Nov 26, 2019 1:49 am

SteveW wrote:
Tue Nov 26, 2019 1:43 am
Hi Ray,

Do you have a copy of the Brown Book ("Workshop and Tuning Manual by W.E. Blower). If so, that has a diagram that shows the correct dimensions of the springs and the locating dimples. With the spring under load so that it's flat, the dimple on the main leaf is 18" from the end with the large eye hole and 18 1/2" from the end with the smaller eye hole. It is that dimple that locates the rear axle position fore and aft. I need to find time to come and see you as you are only just down the road from me. I could bring my copy of the Brown Book with me.

Steve
Hi Steve. Thank you, yes, I have the Brown book. I am familiar with the dimples and their function. I am also aware that leaf springs can be assembled incorrectly and happy that I have got it right.

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Re: New springs alter TC rear axle location.

Post by SteveW » Tue Nov 26, 2019 4:49 am

Hi Ray,

I wasn't really querying whether or not you had assembled them correctly, I was just giving you the dimensions of the spring in case you didn't have them. When I got my car I had exacly the same problem as you described and I traced it to the main spring having been manufactured incorrectly. The overall spring was the right length but the dimple was 1" in the wrong place so the whole axle was that much too far forward.

Ray White
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Re: New springs alter TC rear axle location.

Post by Ray White » Tue Nov 26, 2019 6:30 am

SteveW wrote:
Tue Nov 26, 2019 4:49 am
Hi Ray,

I wasn't really querying whether or not you had assembled them correctly, I was just giving you the dimensions of the spring in case you didn't have them. When I got my car I had exacly the same problem as you described and I traced it to the main spring having been manufactured incorrectly. The overall spring was the right length but the dimple was 1" in the wrong place so the whole axle was that much too far forward.
WOW! That is a long way out.

I should think myself lucky mine is less than 1/2" out!!!

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Duncan M
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Re: New springs alter TC rear axle location.

Post by Duncan M » Tue Nov 26, 2019 10:49 am

Sounds like the new shaft supplied with your 5 speed is fixed length. No slip yoke?

Ray White
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Re: New springs alter TC rear axle location.

Post by Ray White » Tue Nov 26, 2019 11:49 am

Duncan M wrote:
Tue Nov 26, 2019 10:49 am
Sounds like the new shaft supplied with your 5 speed is fixed length. No slip yoke?
Earlier today I checked the spline length for the prop shaft and gearbox (Ford type9) and found it to be a generous 4"....PHEW!

As there should be no problem regarding spline length, all I need to think about is a) shock absorber linkage; b) check strap hole alignment; hand brake cable adjustment; brake pipe/wheel cylinder matching and last but not least wheel position in the arch.

I can't do anything about the last point yet because there is no body on which to attach the wings. I am awaiting a new panelled body.

Ray White
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Re: New springs alter TC rear axle location.

Post by Ray White » Tue Nov 26, 2019 2:18 pm

Edit: Having given the little grey cells something to work on, I have chanced on a much easier solution.
Why not simply drill another locating hole in the axle support, next to the existing one and simply move the axle onto the pin.?

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Steve Simmons
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Re: New springs alter TC rear axle location.

Post by Steve Simmons » Tue Nov 26, 2019 3:03 pm

Personally I would be more inclined to modify the spring or replace it with a correct one than to drill permanent holes in the axle support.
1949 TC8975 / XPAG 9609
1949 TC9849 EXU / XPAG 10507
http://www.mgnuts.com

Ray White
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Re: New springs alter TC rear axle location.

Post by Ray White » Tue Nov 26, 2019 3:08 pm

Steve Simmons wrote:
Tue Nov 26, 2019 3:03 pm
Personally I would be more inclined to modify the spring or replace it with a correct one than to drill permanent holes in the axle support.
Why? It must surely be the most cost effective and practical solution.?

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Steve Simmons
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Re: New springs alter TC rear axle location.

Post by Steve Simmons » Tue Nov 26, 2019 3:21 pm

Because I don't like the idea of drilling holes in a 70 year old car to account for incorrect reproduction parts. I like to think of myself as a caretaker of a piece of history, so I want to respect that history and not modify it needlessly. Not that my car is bone stock or anything, but I draw the line at making permanent modifications without very good reason. Others may feel differently, but that's just how I feel about it. That, and I don't want to be someone else's DPO. ;)
1949 TC8975 / XPAG 9609
1949 TC9849 EXU / XPAG 10507
http://www.mgnuts.com

Ray White
Posts: 56
Joined: Fri Feb 09, 2018 2:22 pm

Re: New springs alter TC rear axle location.

Post by Ray White » Tue Nov 26, 2019 7:21 pm

Steve Simmons wrote:
Tue Nov 26, 2019 3:21 pm
Because I don't like the idea of drilling holes in a 70 year old car to account for incorrect reproduction parts. I like to think of myself as a caretaker of a piece of history, so I want to respect that history and not modify it needlessly. Not that my car is bone stock or anything, but I draw the line at making permanent modifications without very good reason. Others may feel differently, but that's just how I feel about it. That, and I don't want to be someone else's DPO. ;)
I have always felt the same about spoiling a good original car but what I have is not even remotely like that. TC1030 was abandoned as a basket case back in 1960. The body and interior including the seat and dashboard had long since disintegrated and what remained was an incomplete pile of worn out bits that ordinarily would have been scrapped.

My aim is not to try and recreate an original car because it can only be original once but I want it to still be an MG TC and recognisable as such so I am having the headlights restored with the cat's eye lenses and the radiator surround replated. I have commissioned a new body, hood and side screens and the seat, which has been salvaged from another MG, is to be trimmed in leather.

The engine is cosmetically original but has been substantially rebuilt and improved to a high standard by MG specialists with everything balanced. The head has been converted to unleaded and ported for a supercharger with stainless extractor manifold and exhaust.

All the wiring is new and will feature indicators, a dynamater, an electric fan and electronic distributor; sports coil and new petrol pump. The water pump is a six vane upgrade.

The gearbox is a Ford Type 9 conversion with a modified higher first gear, The rear axle will be completely refurbished with an 8/39 (TA) c.w.p. giving a higher ratio of 4.875:1. New half shafts and hubs; new front hubs; king pins and bushes, rebuilt Luvax shock absorbers; new rear and restored front springs, a Panhard rod and new track rod and drop arm ends; VW steering box conversion and new Brooklands steering wheel. 5 new road wheels and tyres. I have also invested in Alfin type brake drums with a bronze master cylinder and wheel cylinders and uprated brake shoes all round.

I will have a new dashboard with a quality walnut veneer instead of vynil and the original instruments are being restored as new by John Marks who owns the British Jaeger brand; the difference is that I will have a combined oil/water gauge; a petrol gauge and a boost gauge for the supercharger. The ammeter will handle the higher alternator output. In addition I have redesigned the scuttle tool box to accommodate a heater which will be plumbed into the bypass and rear cylinder head. In a further departure from the original design I have redesigned the dashboard layout with rare Lucas ivory switches and knobs.

I like an unspoilt piece of automotive history - as my rare 1930 Austin Swallow will testify - but I don't think anyone could place TC1030 in that category.

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Duncan M
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Re: New springs alter TC rear axle location.

Post by Duncan M » Tue Nov 26, 2019 7:51 pm

But Ray, are you not concerned about upsetting the delicate TC suspension geometry? Just kidding. But seriously, if you are going to use those springs you may want to confirm they were indeed intended (spring rate) for the TC, or real close. That link Steve S supplied tells how much weight standing on it will make the spring go flat. Might not be a bad idea to check. 385 lbs.

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Steve Simmons
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Re: New springs alter TC rear axle location.

Post by Steve Simmons » Tue Nov 26, 2019 10:46 pm

I would endorse most of the modifications you're doing. I've done several of them myself. But the thought of drilling holes in an original piece of metal that will confuse the next owner bothers me, so I do personally draw the line there.

I doubt TC1030 is any worse than the new build I started last week on 9849. Basket case doesn't even begin to describe it. It would take hundreds of baskets to hold all the parts. Rotten wood and all! But it will be a proper TC when I'm done, with no drilling or welding involved in any of the mods I perform. It is intended to be a semi-daily driver. Hard to believe when you see this photo from a couple weeks ago...
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1949 TC8975 / XPAG 9609
1949 TC9849 EXU / XPAG 10507
http://www.mgnuts.com

Ray White
Posts: 56
Joined: Fri Feb 09, 2018 2:22 pm

Re: New springs alter TC rear axle location.

Post by Ray White » Wed Nov 27, 2019 1:53 am

Steve Simmons wrote:
Tue Nov 26, 2019 10:46 pm
... the thought of drilling holes in an original piece of metal that will confuse the next owner bothers me, so I do personally draw the line there.

.
That would not be on my conscience.

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