Spitfire & GT6 Forum

Started putting the chassis back together last night and ran into a problem where the mounting bracket bolts for the lower wishbone do not align (centerline distance between bolts and the frame holes). I do remember having to pull a good bit to get the suspension assemblies off, but didn't expect this result going back in and I'm afraid I'll damage threads if I try to bang the thing back in.

However, the bolts and holes are off by a good bolt width. The bolts from the wishbone are on a 14" center. The frame holes look about 1/4" to 1/2" closer together than this. Any ideas I had last night I deemed to risky for causing damage without checking with you guys first. I measured and tried both sides with the same results. You can't put these things on backwards, so there's that.

One idea I had was to use a clamp to squeeze the wishbone together, but I don't think the stiffener that runs between the two arms, near the mounting brackets, will allow this. Another idea was to install the mounting brackets, and then the wishbone itself into them, but I think the problem will just translate. Both of these would also install the assembly under tension, which I was also unsure of.

All of the bushings and the rest of the suspension assembly went together just fine with no evidence of damage and these are the same parts that came off of the car originally. I did make sure that the bolts that the workshop manual calls to remain loose are loose. I also dry-fitted the upper wishbone halves as best I could and they seem to fit just fine.

Again, I was afraid of causing damage so it may just be "one of those things" that have to be rough-housed in there. But, again, if I set one of the mounting bracket bolts into one hole, the end of the other bolt does not cover any portion of it's hole.

I took pics but don't have access to them now. I'll post some after work.

Thanks,
Chris

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I learn something new every day...especially if I am working on my LBC!
Please visit my blog and website at http://www.roundtailrestoration.com
and my YouTube Channel at https://www.youtube.com/channel/UC8LASST0WuNG0-po4hK0Maw

Try installing the mounting brackets first, nut on loose at the back to allow some movement, then the wishbone. That worked for me.

Kinda thinking out loud here, but could the "issue" be the "centering" (or necessary offset of same) of the new bushings in the a-arm?

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http://www.fairpoint.net/~herald948/database/

Since neither the holes in the frame or the shape of the wishbone has likely changed on your car since
it was manufactured in the mid-1960's, I'd be looking elsewhere for the issue.
Did you by chance replace the bushings on the wishbones?

http://www.rimmerbros.co.uk/ImagePopUp.aspx?i=GRID005743

The bushings are pressed into the tubes that are welded onto the inner ends of the wishbones.
The length of the wishbone tubes is shorter than the width between the inner ears of the brackets,
so there is a gap on each side between the wishbone tube and the ear of the bracket of perhaps 1/8".

http://www.rimmerbros.co.uk/Item--i-119451

The bushings consist of an inner steel tube, and surrounding rubber.
The length of the inner steel tube and surrounding rubber matches the width between the inner ears of the brackets.
But the length of the bushing is greater than the length of the steel wishbone tube that it is pressed into.

So the spacing of the brackets, and thus the spacing of the bracket mounting studs (bolts) depends on
exactly how far the bushings are pressed into the wishbone tubes, ie how much is exposed on each side.
Properly installed, there should be about equal amounts of rubber showing between the wishbone tube and the bracket ear.
The drawing in the first link shows this.
But drawings can be inaccurate, so I've attached a pic from one of my cars, showing rubber peeking out on each side.
But if bushes are installed too far in either direction, this will cause the bracket mounting studs to not align with holes in the chassis.

By as much as 1/4".

HTH

I may be doing this same task tonight. Good info here.

Carter,
Thanks for your responses. I went with poly bushes, which came in two pieces. These pressed right in, with the small lip flush against the wishbone holes. The brackets went right over these and, eyeballing it, appear centered.
I've included an old picture of right after I got the suspension assembly to the point it is now. You would have to zoom in to see better since the portion is not the focus.

Thanks
Chris

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I learn something new every day...especially if I am working on my LBC!
Please visit my blog and website at http://www.roundtailrestoration.com
and my YouTube Channel at https://www.youtube.com/channel/UC8LASST0WuNG0-po4hK0Maw

I will add my vote also to remove the mount brackets and install them separately. Then when you place the A arm up to them you will be able to see how and where the bushings need to be adjusted to get them to fit. Keep in mind that even then those should be a snug fit when pressing them into place.

Carter has a very good description of the solution.
Dan

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Dan Aycock
Walla Walla, Wa.
Yellowhawk Valley Spitfires
69, 69, 72, 75, 78, 79 Spitfires

Yeah,
It can be an issue with poly bushings, the little flanges are machined to a fixed dimension that determines the spacing.
The rubber ones feature a bit of axial compliance, the ply ones feature none at all.

Might wind up having to manually trim the poly flanges on one side, and then add washers or spacers on the other side.

There are only two part# for the brackets, 130757 (front) and 130758 (rear) for all years.
Any chance that you may have fitted two rears or two fronts on the same wishbone?
The difference between them is the location of the pivot holes with respect to the mounting stud, not sure that would make
such a big difference, but worth a check before making modifications.

http://www.rimmerbros.co.uk/Item--i-130757
http://www.rimmerbros.co.uk/Item--i-130758

BTW, the mounting to the chassis is more than just a through hole.
There is a stiffener inside the chassis box between the holes, the mounting stud passes through the center.
This prevents the chassis box from collapsing when the stud mounting nuts are tightened down.
The chassis is fairly light gage sheet steel that is folded into box sections and spot welded at the flanges.

I mention this in case anyone is considering 'moving' the holes in the chassis.

Don't forget the issue of the bolts going through the wishbone and bracket first or else the frame will get in the way. You may find the bolt is prevented from turning due to a small weld bump. Not sure if the bolts can be inserted from the opposite direction.

I blamed the previous owner for putting them in wrong when it was actually the factory assembly method
.

Here's my pics. The first show a close-up of how far away the bolt is from going in. The second is essentially the same, zoomed out, to show the other bolt in it's proper place. Again, not the focus of the pic, but it doesn't appear that I have a centering issue. I'm not trying to argue with you guys...obviously something is up, but skeptical dog is skeptical.

Whatever it is, I just wasn't seeing it last night and, like I said, didn't want to make an unfortunate decision. Hopefully I'll get over there this weekend and solve it.

And, yes, I scratched my beautiful red paint

Thanks,
Chris

---

I learn something new every day...especially if I am working on my LBC!
Please visit my blog and website at http://www.roundtailrestoration.com
and my YouTube Channel at https://www.youtube.com/channel/UC8LASST0WuNG0-po4hK0Maw



Edited 1 time(s). Last edit at 2016-12-01 07:15 PM by cmfisher4.

Chris. Since I am in a similar stage of assembly, but still waiting on parts, I measued the outer distance between the open ends of the steel bush tubes on the wishbone. I have two good wishbones and one slightly damaged but they are all withing a 16th of an inch.

Two at 13 15/16 in.
One at 13 7/8 in.

The rear mounting bracket looks to be semetrical and square so I don't think it makes a difference it it's rotated upside down. Obviously the front bracket is different.

I hope this helps.

I was going to ask if you had then all the right way up as there is obviously a difference on one and the other may have the stud actually off center a bit. Not sure of that but worth a check.
Dan

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Dan Aycock
Walla Walla, Wa.
Yellowhawk Valley Spitfires
69, 69, 72, 75, 78, 79 Spitfires

Try this:
Rather than measuring spacing between the tips of the bracket mounting studs,
measure the spacing between the studs right where they attach to the brackets.

It's possible that the wishbones are built with bushing housing tubes at a slight angle,
(on purpose) to impart a preload to the OEM rubber bushings.

When you attempt to bring the stud tips closer together to match the hole spacing
on the chassis, how much 'give' is there?
The rubber ones would deflect, but the poly ones should be a lot stiffer.

Chris, you may have the brackets in the wrong locations. On my 75 the two front brackets have the bolts off center towards the front while the rear brackets have the bolts on center.

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Ernie
1975 Triumph Spitfire

Ernie,
I'll take a look at this. However, I think my brackets have it such the that bolts are off center vertically, not horizontally, so they shouldn't really impact the placement.

Bryan,
I did read you post about your bolt issue. When I put my lower wishbones together, I got lucky and put mine with the bolts on the inside. The workshop manual does show them going the opposite direction (picture, bolt/nut 33/34)...at least the rear bolt is shown that way. I would assume the factory followed the workshop manual's general procedure. It seems as though Triumph only ever expected that the whole assembly, turrets included, come off as a unit, then worked on the bench.

I plan on getting over to the garage on Sunday, so I'll update my findings.

Cheers,
Chris

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I learn something new every day...especially if I am working on my LBC!
Please visit my blog and website at http://www.roundtailrestoration.com
and my YouTube Channel at https://www.youtube.com/channel/UC8LASST0WuNG0-po4hK0Maw



Edited 1 time(s). Last edit at 2016-12-02 10:35 PM by cmfisher4.