more on rear leaf springs.

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Ray White
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more on rear leaf springs.

Post by Ray White » Thu Oct 17, 2019 12:27 pm

I am replacing the rear springs on my TC and having great difficulty in fitting the (big) spring eye to the mounting boss. The old spring came off easily but the new one just doesn't want to go on.

Anyone had this problem?

Polite suggestions as to what I can do with my springs welcome!

Ray.

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Marv
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Re: more on rear leaf springs.

Post by Marv » Thu Oct 17, 2019 11:29 pm

Pictures or more info needed for clarity on your situation. However, taking a guess, a common mistake sometimes is to have the rear shackle plates (item 63) orientated such the rear spring eye is wrong way round. The spring wants to "flatten" making it very difficult to install.

The rear spring eye goes above the pivot point of the rear shackles in the proper orientation.
rear-axle-tc.jpg
rear-axle-tc.jpg (43.93 KiB) Viewed 1051 times

Ray White
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Re: more on rear leaf springs.

Post by Ray White » Thu Oct 17, 2019 11:41 pm

The difficulty I am having is getting the front spring eye of the rear spring onto the silent block bush/pin (item 62A/7) in your illustration. No problem at the other end of the spring.

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Marv
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Re: more on rear leaf springs.

Post by Marv » Fri Oct 18, 2019 12:22 am

Put that end on first, A little grease on the silent bloc, snug it up and rotate the rear eye into position with only the inside shackle plate in place, install outer shackle plate and snug everything up. Unless I've missed something, it sounds like you've got the rear eye and shackle plates in place first.

Ray White
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Re: more on rear leaf springs.

Post by Ray White » Fri Oct 18, 2019 5:41 am

I have tried offering the front eye on the silent block first with grease and it won't go on. Not even with help from a persuader.!

I wonder if the eye has been made a shade small.

Can you tell me how the pin (with the silent block bush) is fitted onto the chassis please?

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Marv
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Re: more on rear leaf springs.

Post by Marv » Fri Oct 18, 2019 6:14 am

That pin is mounted to the frame rail via a through hole with a nut and washer on the inside. Based upon your question I'm guessing it was not removed and the Silentbloc is new. So with the pin O.D. being larger than the Silentbloc I.D. (which is a metal bushing), you have either a Silentbloc that is the wrong one for a TC that just happens to be the right outside diameter but the wrong inside dia. Or, the inside metal bush has manufacturing mishap in a raised lip on it that prevents it from accepting the frame mounted pin or a wrong metal bush from the git-go. Are you replacing both sides and if so, do both sides present the same situation. For the record, I did not have any problems with mine, they were Moss supplied items.

I would measure the inside diameter of the bush in the Silentbloc against the outside diameter of the frame mounted pin. If the interference is small, you can probably ream or carefully drill the bushing out to a larger diameter. The fitment is SFNS (slip fit-no slop) as it does have a small degree of rotation on the frame pin and wear will be accelerated if you have a loose fitment.

If the difference is so much as to compromise the thickness of the bushing wall if you do any machining to it, then I suspect you have the wrong Silentbloc and should consider getting a couple of new ones from Doug at FTFU.

Ray White
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Re: more on rear leaf springs.

Post by Ray White » Fri Oct 18, 2019 6:51 am

Thanks for that, Marv. No, the silentblock bush is original and the pin on my car appears to be housed in a tubular extension to a chassis cross member. I can see no obvious way of removing it as everything is riveted.

As it happens, I have now succeeded in fitting the spring... I made certain there were no burrs on either the spring eye or the silent block bush and applied a slight chamfer to the edges to get things started. I used a heavy brass drift and tapped the spring eye on until there was sufficient thread showing and used the nut and a big washer to draw the spring fully on. Phew!

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Marv
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Re: more on rear leaf springs.

Post by Marv » Fri Oct 18, 2019 7:06 am

Whew, that's good, I was incorrect in my statement on mounting the pin. I believe, although I'm not positive as I've never removed one myself, that that pin unscrews from the frame. No access to allow for a nut and washer on the TC.

Problem solved anyway. :thumbs: :lol: :thumbs:

Ray White
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Re: more on rear leaf springs.

Post by Ray White » Fri Oct 18, 2019 7:58 am

It hasn't been a walk in the park fitting the other end either. The large shackle pin (lower) has castellated nuts and split pins at both ends. However, the nut on the inside end has been filed down and a distance piece added. I found a split pin had been sheared off so after removing it's remains I tried fitting a full size nut but it wouldn't tighten far enough. As there is no apparent damage I imagine the thread must have stretched and that would have led a p/o to thin down the nut and add a distance piece so that a split pin could be fitted...

Ideally I should replace the shackle pin. I imagine there is a risk of the pin shearing under load?

A new pin is at least £135. :eek:

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Steve Simmons
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Re: more on rear leaf springs.

Post by Steve Simmons » Fri Oct 18, 2019 8:08 am

Yikes. Well, maybe that pin is suspect and maybe it isn't, but the peace of mind might be worth the effort and expense. You have enough to think about at 60MPH in a TC without constantly wondering if your shackle pins are going to snap.
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Marv
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Re: more on rear leaf springs.

Post by Marv » Fri Oct 18, 2019 8:16 am

Sounds iffy at best Ray, you probably should bite the bullet and get a new pin. My best price would be close to $160 U.S. from my supplier. Moss is listing it at $199.99. If you can get it at £135, that's about as good as it's going to get. We often have reasons to question the good intentions and bad decisions by the P.O.'s., many times with four letter words. :x :? :cry:

Ray White
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Re: more on rear leaf springs.

Post by Ray White » Fri Oct 18, 2019 10:39 am

So can leaving out one or more of the 3 loose leaves improve/soften the ride? I only ask because all the shock absorbers will have been rebuilt so they will be pretty stiff.

OR is there a downside in terms of handling?

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Marv
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Re: more on rear leaf springs.

Post by Marv » Fri Oct 18, 2019 11:07 am

Personally Ray, I'd leave the springs as is. Being that they are a minimum of 70 years old says that they have been "Age" relaxed anyway unless a PO has replaced them along the way. I had my shocks rebuilt and in the process I rebuilt my springs as well. no new leaves, just a freshening up to remove the rust and epoxy paint and then I inserted a strip of slippery Teflon self adhesive tape between each leaf. New poly bushes, new silentblocs and back together, As new to "factory issue" as one can get without going to new aftermarket springs I guess.

Downside due to handling? I'll leave that for others to address, I guess I wouldn't want to take that chance given the work involved in reversal back to original. :? :? :?

Ray White
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Re: more on rear leaf springs.

Post by Ray White » Sat Oct 19, 2019 12:28 pm

The rear springs are new, Marv ...hence the fitting problem previously discussed. I have taken them apart and offered up the end of each leaf to the bench grinder; rounded off the corners and gently chamfered the edges. I have applied corn head grease to the springs and fitted them with new (small) shackle pins and poly bushes all round.

I just wondered if any readers had experimented with leaving out one or more of the loose springs to improve the ride?

timberstone
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Re: more on rear leaf springs.

Post by timberstone » Sat Oct 26, 2019 4:16 pm

Yes, once I accidentally left out some leaves but the ride was not smoother, just easier to bottom out.
What gives a smooth ride is having original springs thoroughly de-greased and cleaned then re-arched, assembled accurately and completely with the teflon strips between the leaves.
If you do not have the original springs, but replacements that come with squared ends, then a suggestion might be to grind the ends to look like the original with rounding and tapers. Make sure this is all done with fine grinding and leave the teflon strips proud of the ends, so that the ends do not dig into the leaves above them.
You might still notice that going over normal road bumps makes the frame and chassis flex. This is also part of the built in design for springing for the TABC series cars. This is an original and defining characteristic of the series.
Rebuilding the shock absorbers can also affect the ride smoothness, but not sure whether these shocks can be adjusted.
During the suspension rebuilding process, I also had all the spring leafs powder coated. This changed some of the dimensions and characteristics of the springs, but I cannot say this improved or smoothed the springing action. Also, doubt that powder coating is a reliable substitute for the teflon strips between the leaves, but does keep the leaves cleaner and less likely to accumulate grit.

Franz Tenbrock
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Re: more on rear leaf springs.

Post by Franz Tenbrock » Sat Oct 26, 2019 11:16 pm

Hello
when i got my car last summer, i got a bag off tools and parts with it
also 2 springs, now laying in the garage, no chance to look at them in the moment
but my question is
what kind of teflon stripe you use
you have a link to it
in order for the springs to be able to glide, it is necessary to glide well
so teflon should be a good modern tool to let them glide
perhaps i can dismantel the old springs and try them with teflon between

but some work with my new old YA
this car has also springs like this too

i hope my english has made progress too last year,
sometimes with translator most without
Best Regards
Franz

English better every day ;-)
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SteveW
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Re: more on rear leaf springs.

Post by SteveW » Sun Oct 27, 2019 3:51 am

An alternative to using teflon between the springs is to make a mixture of grease and carbon powder (bags available on e-bay). I stripped my springs down to the individual leafs (leaves?), took them back to bare metal, ground down the ends to round them (so persumably mine are not original) and then painted them with POR15 before reassembling with the grease mixture. One other change that I had to make was that the 'dimple in each of the main reaf leafs was 1" in the wrong place - too far forward (further confirming that they are not original) so I had to have new ones of those made. That also explains why the rebound hoops were on the car seat when I first got the car as they didn't fit with the incorrect rear leafs as they brought the whole axle forward by 1". It took me ages to spot that that was the problem!

Duncan M
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Re: more on rear leaf springs.

Post by Duncan M » Sun Oct 27, 2019 6:20 pm

SteveW's idea of mixing graphite with grease is popular. Some prefer silicone grease. More than a few people think the whole notion of the teflon sheets is rubbish, as they do nothing to repel/displace water and dirt.

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Marv
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Re: more on rear leaf springs.

Post by Marv » Sun Oct 27, 2019 9:48 pm

Oh, I dunno', …. but repelling/displacing water and dirt from betwixt the leaves seems not a bad thing to have happen. Lots of thoughts positive from a number of owners on that side of the coin too I'd bet. Grease is an attractor and retention element for dirt and grime. But, in the grand scheme of things, it all boils down to owners preference regardless.

Ray White
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Re: more on rear leaf springs.

Post by Ray White » Tue Oct 29, 2019 3:55 am

I have always used corn head grease and it has served me and many others well.

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