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MG TD TF 1500 - Rear Spring

So I took off the passenger rear spring to replace all the bushings and noticed this extra leaf - No 8? and it is drilled off center. The extra leaf, small as it is, seems to be the norm on the new springs being offered now. Not sure why it is drilled off center? The extra portion is towards the front.
I replaced the drivers side when I was back in Maine several years ago. It seems to be drilled in the center. Making it symmetrical. Could just be a red herring but though I would ask. Is there a reason it is not drilled in the center of the leaf?
The other question is on the Silent block bushing. it show's in the WS manual two washers (fiber type when they come) I take it these go directly on the ends of the bushing and not under the head of the bolt and nut that hold it in place.
For anyone doing this work before putting on the running boards - note* Bolt goes in the chasse, facing out with the big nut on the outside. Or you wont get it out later.

This is all part of the work to find out why my TD started tending to go right when accelerating and then left when taking your foot off the gas. Not a lot but noticeable.

Figured I would make sure all the geometry of the rear end is in order first. Also replaced the rubber bushings and U Bolts.
Rod

Rod





Rod Jones

Rod, maybe an optical illusion, but the newer spring looks to have a higher arching than the old one. TF springs have the same material specs but a flatter curve could there have been a mixture?

I don’t have the figures to hand but I was under the impression that ALL of the leaves have the holes offset from the centre with the long end to the front.

Chris
C I Twidle

Thanks Chris,
The slightly less curve in the springs is because the one that was on the TD for 15 years has sagged a tad. Possibly due to my increase in weight :) I have now lost 100lbs over the passed 3 years and I think it will help going forward. The spring I put in when back up in Maine, does indeed have the longer side to the rear. Hard to get wrong as the silent block fitting is to the front. Seems the last bottom leaf could be the wrong way round but I wonder what difference it would make being so short.
Interestingly the one on the other side is symmetrical on the last leaf?


Rod Jones

Rod: Most T cars have one flatter spring if they have not been rearced/replaced. This is on the drivers side since most of the time they were driven solo. Not unusual.

Some people mix and match the leaves between the two springs to even it out or have leaves replaced/rearced to bring them back even again.

As you noted the leaves are a bit offset so pay attention and use your original one as a guide if you get confused.

I think that the bottom one on the new spring has been drilled wrong. But it is not that big of a deal since it really does not support that much of the weight.
Christopher Couper

Thanks Chris,
That was the reason to change the spring when up in Maine 5 years or so ago :)
So to make it symetrical and also fit the rubber pads corectly, I redrilled the bottom extra 8th leaf that does not show in the WSM - I guess it is an addition by the new supplier, (India or China?)
I also managed to remove and replace the Silent block bushing. Bit of a job without a Press, but it got done with a couple of sockets and a vice. I don't think I will do this on the drivers side, what is there is in very good condition. Will however do the new polly bushings at the rear. Also the fiber washers at the silent block end.





Rod Jones

I think Chris is on the money. Maybe ask the question of the asymmetrical springs of TC owners? This question was posed by one of the TTORC TC owners and was referred to the TC gurus in the west. It appears that this asymmetry is not unusual. Also check the eye to eye measurement of the new and old springs and compare them. Thicker inter-leaf spring pads will significantly reduce this measurement and can create havoc when the rear shackle springs up without warning. Owners here have reported substantial panel damage to the rear apron and guard on newly restored cars. See pic showing measurements by Micheal Grogan and the same pic posted by Guenter. These are in my gallery, but I can't substantiate the measurements. The other pic illustrates what happens when that distance is shortened, caused by using the thicker circular inter-leaf pads. I threw the new pads in the bin and reused the old ones. No prizes for guessing where the new pads came from. Caveat emptor. Cheers
Peter TD 5801





P Hehir

Got all the rear suspension back together and did fit the fiber washers at the silent block end. They were not there and I can't remember actually putting them in before. Bit of a game getting them in as it is tight. two people would have been good. Possibly there only for noise abatment as there is pressuois little movement at this point.
So now that job is out of the way and everythgin is repalced. I can look else where for the tracking issue. Alignment etc. and the trunions. Oh joy.

Rod Jones

When this was being discussed in the past I was reminded not to tighten the shackle bolts until the suspension was under load. From memory it was mainly to ensure that the bushes weren’t under too much shear load. I also found that the hangers settled into a better position when I complied with this idea. It’s also worth reiterating the need for the rebound straps to be in place.
Chris
C I Twidle

Rod: If there were no fiber washers when you took it out it's possible the brackets had bent in just a tiny bit after being clamped down for years without them.

But IIRC it is kind of a bear to get all that in there.
Christopher Couper

The silent block bushings don’t require replacement unless you notice the car being a bit twitchy on de/acceleration.
W A Chasser

You got that right Chris. Working alone it was quite a wiggle to get it all in but the drivers side was a lot easier than the passengers. So thankful for small wins.
Bill, My issue was that my TD would move slightly to the left on accelloration and then move to the right on Deceloration. Front end looks good for play so desided to have a go at the rear. Replace all the bushings with polly and the rubber bolcks and replace the U bolts. Make sure everythgin was tight. I did replace the silent block on the passengers side and it was a real bear without a shop press, but got the new one in and positions correctly. Drives side I left alone as the condition was really good and it was only in there 5 years.
I made a gauge out of 2x4 and sorted out the tracking utilizing the wheel rims. I have good chrome wires and they have very little run out. Checked in 2 places. I set the tracking to Nil and it WAS a tad out.
Hoping this was my problem. Will know after a road test.
Rod Jones

I decided to reactivate this thread because I am still a little unsure about the best way to address the rear springs on my TD. I have read lots of the archived threads but am still a little unsure. My main concern is the possible "flipping" of the rear shackle as described by Peter Hehir. I have two sets of springs which have an eye to eye unloaded measurement ranging from 40 3/4" to 41 1/2" unrestored. None of the measurements are the same. Obviously, the longest eye to eye measurement is 1/2" shorter than the 42" in the manual. One set appears to have a camber that is a little "flat" (that is the longer eye to eye set). The other set has a camber that is a little "high" making it the shorter set eye to eye. What and where are the critical tolerances on the springs? None of these are near the 39" that Peter mentioned is some post I read. Would you take the springs to a shop to be returned to the original specs, or are these numbers acceptable?

Thanks for all of the expertise,
Jim
JV Smith

The shackle can only flip if the axle strap is not in place. It can only happen on full droop when the shackle passes in line with the spring.
We used to reverse shackles to lower the car on Y types for "banger" racing in the 60's. a gas axe sorted the front. The Y type owners will probably send out a hit squad on me now ;-}
Ray TF 2884
Ray Lee

Thanks Ray. One more question for the group. Is it true that I should never sandblast springs? If so, what is the cleanup of choice?

Jim
JV Smith

Jim I left my spring leaves soaking in molasses for a few weeks in a length of 100 mm waste pipe.

The rebound straps were missing fromTF2071 so I fabricated some from 25mm flat steel. I was not completely confident that they were the correct length or substantial enough to stop the hangers inverting. My neighbour came up with the devices shown made from 25x6 steel. Sorry about the thumb but i think you can still make out the one small bolts to locate them. I am now confident that my hangers will stay the right way up!

I will also add that now the car has been fully assembled with a full tank for a few weeks the springs have settled into a better position.
Chris





C I Twidle

Chris,
I like your solution. But I have my original rebound straps and they are in good condition except for the rubber. I am going to have to figure out a replacement for the rubber, so if anyone has done that, what did you do? So, is everyone saying that unless the rebound straps are not installed, or somehow fail, I don't have to worry about the shackles reversing?

Thanks,
Jim
JV Smith

Jim. Spring steel is relativly tough. I cant see that sandblasting would impact them, but then I don't do a lot of blasting.
Bruce Cunha

I think the TF with it's flatter spring is less likely to flip than a TD.As far as I know, the only occasions of flipping have been during assembly when the car has been lowered off the jacks without the strap in place. I have never heard of it happening on the road.
Ray TF 2884
Ray Lee

There were at least three occasions that I've been made aware of here in Sydney Ray with beautifully finished cars rolling out of the driveway. They all had used the thicker circular inter leaf rubbers purchased from the same supplier, thus reducing the eye to eye measurement, which was responsible for the rear shackle springing up without warning. Fortunately I had my rear guards, the tank, rear apron off and the straps were on and fixed when it happened in front of my eyes. The Ray that I was working with both witnessed it. After some serious head scratching the issue was finally traced back to the circular pads. The assembled springs were marked out on the garage floor in chalk, then the springs were stripped, the original pads reused and laid against the earlier mark out and marked out again. The difference was substantial. Once reinstalled with the original circular pads - which were still in remarkably good condition, (it was 1970 rubber and the car hadn't been driven:) and the problem on both sides had magically disappeared!

It's an easy test to perform yourself. If you have a set of assembled springs. Adopt the procedure above, introduce some thicker plastic packers in place of the circular pads, assemble, mark it out on the floor and observe the shortened eye to eye measurement. Install and then enjoy the fun. Just remove the guards and the rear apron first. Unless money is no object :-) Cheers
Peter TD 5801
P Hehir

I will modify what I said.
With the correct springs fitted it cannot happen with the straps in place.
With incorrect springs it should be obvious that the shackle angle is wrong.
Ray
Ray Lee

The springs are still in my car. They were there when I purchased it in 1969 and I drove over all manner of roads at speeds that I shouldn't have and never had a problem; not for 18 months. I'm just reporting what actually happened to owners here in Sydney when replacing the circular pads. The eye to eye measurement is CRITICAL. I accept that age and weight is a factor and that springs will flatten over time. I know that thicker pads will increase camber to the point where the rear shackle WILL spring up and can and has done substantial panel damage. My suggestion is to simply note this dimension before and after the rebuild and then decide how you wish to proceed. I don't know what the desired dimension is or the temper of the spring, how long springs will last, whether its desirable to swap springs from side to side. I'm simply responding to the post from JV Smith and issuing a caution... That's all I can add to this discussion. Cheers
Peter TD 5801
P Hehir

When I rebuilt my TF (1970) I had the springs seen to. The company made a new top spring and cut the old one, and the others, down to fit one level down. The result was that I had an extra, small, leaf in the spring. Rather like the spring in Rod's photo.
D A Provan

This thread was discussed between 17/03/2020 and 04/08/2020

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