Vixen S2 rear upright pivot pin

Vixen S2 rear upright pivot pin

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Discussion

bergxu

Original Poster:

382 posts

164 months

Saturday 4th February 2017
quotequote all
Hey all,

Working on rebuilding the suspension on my Vixen and got the front done which was an absolute bear thanks to every bolt being seized in its respective bush sleeve but now that's sorted, time to move on to the rear and I need help in understanding the rear upright lower pivot pin. I presume it's a singular long affair which goes through the bottom of the upright and, once the tapered roll pins are knocked out (hopefully), I can tap the pivot pin out from rear to front as I see a thick spacer on the front side of it. Am I correct in my thinking? In the event the pin is seized solid in the upright, is a MAP gas torch too hot to use to help free it? And if so, what's the prescribed method of removal?

bergxu

Original Poster:

382 posts

164 months

Saturday 4th February 2017
quotequote all
Pic of thick spacer...


Clive-sz8cz

110 posts

111 months

Saturday 4th February 2017
quotequote all
DON'T try to hammer the tapered pins out!!!!!! They aren't tapered, they have a notch in them that the pivot pin passes through so all you can do is slacken them slightly so they take the pressure off the pin. I found out the hard way and had to have the casting welded. Once the pivot pin is out you can remove the retaining pins.

Edited by Clive-sz8cz on Saturday 4th February 12:09

Dollyman1850

6,319 posts

257 months

Saturday 4th February 2017
quotequote all
NO NO NO NO!!!!!

DO NOT TRY TO REMOVE PINS shout

The only way to remove the rod is to cut flush with casting then centre drill carefully jigging to get dead centre then carefully pressing the pivot rod out.
The cotter / jiggle pins call them what you will are a small pin which have a half round cut into them which is used to tighten against the rod to stop it rotating in the casting.

These have the nuts removed to take pressure off the pivot pin which can then be drilled / removed.

More uprights are scrapped by well meaning restorers than are scrapped during use!

If you are careful you can drill to just inside wall thickness both sides then push out, cut flush again and push back t'other way so you can remove centre piece that is left between the 2 pin points.

N.


Edited by Dollyman1850 on Saturday 4th February 11:36

Clive-sz8cz

110 posts

111 months

Saturday 4th February 2017
quotequote all
I managed to remove the pivot pins by pouring a load of Plus Gas (or similar) into the casting 'well' that the pins pass through (the pin is visible if you look in the well on the the back of the hub) and leaving it to marinade for days. Alternate heating/cooling and gentle'ish hammering in both directions eventually released them. Patience is a virtue!

bergxu

Original Poster:

382 posts

164 months

Saturday 4th February 2017
quotequote all
Thanks for the replies gentlemen, I do understand now about the two tapered pins but I guess what I also need clarification on is in the second picture that I posted of the front edge of the pivot pin, there is that thick spacer which appears to be part of the pin itself or am I incorrect? That is the only reason why I asked about removal of the pivot pin itself is because I don't see how I am going to get to that outer wishbone bushing otherwise.

Dollyman1850

6,319 posts

257 months

Saturday 4th February 2017
quotequote all
bergxu said:
Thanks for the replies gentlemen, I do understand now about the two tapered pins but I guess what I also need clarification on is in the second picture that I posted of the front edge of the pivot pin, there is that thick spacer which appears to be part of the pin itself or am I incorrect? That is the only reason why I asked about removal of the pivot pin itself is because I don't see how I am going to get to that outer wishbone bushing otherwise.
Nope thats just a big corroded washer.
I would come about 10mm back from where the pin exists the casting and hacksaw them off from there. Then carefully remove whats left of the bush / inner sleeve by hacksaw cutting / angle grinding the top surface of the sleeve so you can split it away from the pin. The 2 10mm exposed ends can then be filed off square so you can then make up a jig sleeve to allow a perfectly centred drill which can now be progressively enlarged into the pivot rod. and you can start the process of removal.


N.


Edited by Dollyman1850 on Saturday 4th February 13:33


Edited by Dollyman1850 on Saturday 4th February 16:07

bergxu

Original Poster:

382 posts

164 months

Saturday 4th February 2017
quotequote all
If not necessary, I certainly don't want to remove the pivot pin from the upright. All I'm looking to do is to be able to slide the wishbone off so I can fit new bushings. If you say that spacer is in fact just a large corroded washer, wouldn't I be able to free it up with my torch so I can slide it off the pivot pin?

280i

160 posts

159 months

Saturday 4th February 2017
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Is it a good idea to replace this pivot pin? My car still has its original and it still looks to be in good shape? I know the new replacements are said to be made out of harder material. I have a 4 spring/damper set up so the stress on it should be a bit less? On my car there is no rust on it and I would think it would come out easy.
Thoughts? Should I try to replace it proactively before there is a problem in the future with it? my car has only 17K original miles.

Astacus

3,488 posts

241 months

Saturday 4th February 2017
quotequote all
These pictures of my rear uprights might be helpful to understand the assembly

This is what the pins look like, the rod passes through the cutout and is held when the nuts are tightened against the casting



This is the assembly


Dollyman1850

6,319 posts

257 months

Saturday 4th February 2017
quotequote all
It looks pretty bent to me?
The bushes are seized and the pin has steel washers corroded to it

If you are going to do a job then do it correctly.
If you don't have the ability or the gear to do some of the tasks then farm it out to someone who can.
Its too difficult is seldom a good reason not to do something.

Put it another way.. The pin is bent so it doesn't have the same strength it used to have??

If your uprights still have a straight pin, are corrosion free and all the bushes and tubes come off it in good nick then fair enough.. leave it alone.

N.


Edited by Dollyman1850 on Saturday 4th February 16:10

bergxu

Original Poster:

382 posts

164 months

Saturday 4th February 2017
quotequote all
Thanks for the breakdown photos, those helped. Yes, I intend to do the job correctly, however I need information, hence my original post. I was not aware that one could even obtain new pivot pins but by way of this thread, I see that they are in fact, able to be had. Mind you, I'm in the US so we don't exactly have a load of TVR parts specialists here save for essentially one guy.

I'll give Dominion a call and see if he can supply me new pins.

62GRANTIII

199 posts

200 months

Saturday 4th February 2017
quotequote all
Easy to make yourself or a local metalworker
Bit of 1/2" diam EN16 steel rod, ends threaded 1/2" unf ..... UNified Fine, an American thread
Just measure length of your rod & length of thread at each end.

For your info the 2 cotter pins are basically a 3/8" bolt with head cut off & then the cut out can be simply done with a half round file
Nowt technical lad !!

Dollyman1850

6,319 posts

257 months

Saturday 4th February 2017
quotequote all
62GRANTIII said:
Easy to make yourself or a local metalworker
Bit of 1/2" diam EN16 steel rod, ends threaded 1/2" unf ..... UNified Fine, an American thread
Just measure length of your rod & length of thread at each end.

For your info the 2 cotter pins are basically a 3/8" bolt with head cut off & then the cut out can be simply done with a half round file
Nowt technical lad !!
EN16T
N.

bergxu

Original Poster:

382 posts

164 months

Saturday 4th February 2017
quotequote all
Excellent information, thanks! Certainly not complicated to do by any stretch and admittedly, out of a bit of laziness I figured I'd pick the collective brains round here but I really appreciate the information. I've left the pivot pins to soak in penetrant so after a few days we shall see how much luck I have getting them out without having to resort to cutting anything else.

bergxu

Original Poster:

382 posts

164 months

Sunday 5th February 2017
quotequote all
One question about making the new pin from scratch; would rolled threads be preferable to cut threads since they are stronger?

Dollyman1850

6,319 posts

257 months

Sunday 5th February 2017
quotequote all
bergxu said:
One question about making the new pin from scratch; would rolled threads be preferable to cut threads since they are stronger?
Not required. No tensile load on the threads.
N.

anonymous-user

61 months

Sunday 5th February 2017
quotequote all
Dollyman1850 said:
NO NO NO NO!!!!!

DO NOT TRY TO REMOVE PINS shout

The only way to remove the rod is to cut flush with casting then centre drill carefully jigging to get dead centre then carefully pressing the pivot rod out.
The cotter / jiggle pins call them what you will are a small pin which have a half round cut into them which is used to tighten against the rod to stop it rotating in the casting.

These have the nuts removed to take pressure off the pivot pin which can then be drilled / removed.

More uprights are scrapped by well meaning restorers than are scrapped during use!

If you are careful you can drill to just inside wall thickness both sides then push out, cut flush again and push back t'other way so you can remove centre piece that is left between the 2 pin points.

N.


Edited by Dollyman1850 on Saturday 4th February 11:36
Can the rod not be knocked out once the scalloped pins are loosened? - if in reasonable nick that is.
I've done this with other setups but the problem then was the scalloped pin rotates and locks the rod as it moves

bergxu

Original Poster:

382 posts

164 months

Sunday 5th February 2017
quotequote all
@Dollyman; thanks. Duly noted. Cut threads will do nicely then.

@V6Pushfit; that's what I was thinking as well however given the corrosion I see on mine, I may have to resort to drilling and cutting but I'm certainly going to try knocking it out once I loosen the pinch bolts up. I've left it to soak with the inside cavity of the upright doused with penetrating oil so we shall see. If no go, I'll follow the suggestions here of drilling it out and will make a new one from stock material.

Edited by bergxu on Sunday 5th February 13:37

Stevo302

395 posts

145 months

Tuesday 7th February 2017
quotequote all
Clive-sz8cz said:
DON'T try to hammer the tapered pins out!!!!!! They aren't tapered, they have a notch in them that the pivot pin passes through so all you can do is slacken them slightly so they take the pressure off the pin. I found out the hard way and had to have the casting welded. Once the pivot pin is out you can remove the retaining pins.

Edited by Clive-sz8cz on Saturday 4th February 12:09
One of my castings had been welded, some on here condemned it. So I'm getting some new ones from Nigel Reuben. Went to see Nigel the other weekend and his place is amazing! Better to be safe than sorry. Not cheap but worth it.