Who's going to be first to mention wishbones?

[chris.richard]

;)

[Stratos]

Don't get me started on them!

My car's an Allora, so most of my situation wouldn't be relevant to Hawk or Corse owners, but front wishbones have been the bain of my life over the last few months.

[mogul_x]

All,

Since the subject has been broached, I wanted to ask about the assembly of the front upper control arms to the frame on a Hawk.

My car was shipped without the suspension attached to the car. The control arms were shipped as a loose sub-assembly, with all of the assorted hardware installed. The thing that has me puzzled is the correct sequence of spacers and washers required to establish the relationship of the control arm to the chassis tub to the shock absorber.

Could anyone post a very close-up picture, or list the correct order of assembly for the components? I tried installing the arms with the hardware oriented as shipped, and it didn't seem to be quite right. The order of assembly I tried, from front to back along the pivot rod, is as follows:

Nyloc nut, flat washer, special zinc plated washer #1 (supplied with kit), nylon bushing (in front leg of control arm), special zinc plated washer #2, front suspension attachment boss on frame, spacer tube, shock absorber, spacer tube, special zinc plated washer #3, nylon bushing (in rear leg of control arm) rearward suspension attachment bracket on frame, flat washer, hex nut, jam nut.

The above order of assembly resulted in both bushings in the control arm resting up against the brackets on the frame. There is a fourth zinc plated washer, that I didn't install, that I assume should go in between the rear nylon bushing and the rearward suspension attachment bracket. If I put that fourth washer in, then there is a space between the front bushing and the frame, and I don't think that the spacer tubes fit anymore.

There were a bunch of extra spacers included in the kit, which I would guess can be used to adjust the position of the shock along the pivot rod. As for that fourth washer - do I put it in and add shims between the front bushing and the frame, or do I leave it out?

I apologize if this is hard to follow. I've re-read it a few times myself, and I'm not sure if it would make sense to anyone but me.

Thanks

[rutthenut]

Originally posted by mogul_x
The thing that has me puzzled is the correct sequence of spacers and washers required to establish the relationship of the control arm to the chassis tub to the shock absorber.

I must say, this is one of the things I would particularly liked to have seen drawn as a schematic in the build manual. It's not obvious as to which washers, spacers and so on go where - at least when first trying it out.

Many of the omissions can be excused due to the different options for donor parts and so on, but this is a standard bit of kit assembly.

But having put the car together, the omissions don't seem to be such a problem - it's during the build that the curses tend to fly!

I'll see if I can get a useful piccie or two of the upper arm assembly, unless someone else has already done so.

Also, the alternative spacers are unlikely to be for the upper suspension pivot bolt, as that should really only go in the one position. They can be used to change the position of the inner wishbone rose joints for front and rear lower arms, or for the tie rods, if there is any need to move these to an off-centre position.

[rutthenut]

Originally posted by mogul_x
The order of assembly I tried, from front to back along the pivot rod, is as follows:

Nyloc nut, flat washer, special zinc plated washer #1 (supplied with kit), nylon bushing (in front leg of control arm), special zinc plated washer #2, front suspension attachment boss on frame, spacer tube, shock absorber, spacer tube, special zinc plated washer #3, nylon bushing (in rear leg of control arm) rearward suspension attachment bracket on frame, flat washer, hex nut, jam nut.

The above order of assembly resulted in both bushings in the control arm resting up against the brackets on the frame.

I think that actually sounds about right, except for the rear nylon bushing, which I would expect to be fitted with the large washer to the rear. But the car I'm looking at in my garage has a slightly different setup, so apologies if that comment is wrong for you!


The front 'leg' of the wishbone uses a pair of the large washers, fitted either side of the nylon bush, with its metal insert, as well as a normal washer and either a nyloc nut or a pair of locked nuts at the front.

The bit between the two chassis points uses a spacer either side of the damper top mount (may be different if you have rubber-bushed units such as Spax, or rose-jointed versions). Then there is another of the large/thick washers next to the nylon bushing on the rear 'leg' of the wishbone, and a washer to the rear of that, flush with the chassis section, then a normal washer and lock nut assembly on the other end of the through-bolt, in the cockpit area.

The thing you must note with the nylon type bushes is that the metal bush which runs through it must be clamped up tight by the through-bolt (at the rear too). The large washers on either side of the bush help in this matter.

The metal bush should not rotate on the bolt, or it will rapidly wear out. The nylon bush should experience all the friction during rotation of the wishbone. That does lead to an amount of 'stiction' when first installed, but better that than free play in metal-on-metal joints later.

When fitting together for final assembly, it would be a wise move to include plenty of long-life lubrication on the through-bolt, bushes, spacers and the chassis. You are bound to want to take this off again some time, and if it doesn't have copaslip or some other grease in there it is very likely to seize up over time.

Attached picture shows just the front leg of the wishbone, as my camera batteries died when I tried to take a photo of the inner part...

[rutthenut]

And another photo of the same part, slightly different perspective.

[rutthenut]

Having re-read your comments describing the problem, I don't have an exact answer - despite my previous reply.

But if you have the parts all loose and unattached, other than having the nylon bushes (and their metal inners) attached to the wishbone ends, you should be able to offer up the wishbone so that the rear leg is flush with the front face of the rear chassis mount (that make any sense). All without using the central bolt at this point.

If the rears of both nylon bushes touch the frame in this position, then simply adding the large washers to the rear of each will move the whole wishbone forward by just that amount. Then you would also add another large washer to the front side of the rear nylon bush and see what the remaining gap is from there to the rear side of the front chassis mount. That is the distance that has to be filled with spacer(s) and the top mount of the damper, which you will hopefully be able to do with the supplied spacers.

If you find that the nylon bushes don't both touch the frame, then that will indicate where you may include a large (or small?) washer at either end to take up the free play. I've not needed to use shims at all for this area of suspension mounting. There is also a very small amount of flex in the wishbone arms as you tighten up this assembly, but you don't want to be forcing that into place as you do this.

Anyone else got comments, from more recent assembly of a Hawk kit? My memories are somewhat rusty on this stuff nowadays!

[mogul_x]

Originally posted by rutthenut
If you find that the nylon bushes don't both touch the frame, then that will indicate where you may include a large (or small?) washer at either end to take up the free play.

That's the condition I'm seeing, all right. Glad you were able to decipher my gibberish. When the rear bush is touching the front surface of the rear mount on the frame, the front bush is not touching the front surface of the front mount. As it happens, the gap is almost exactly the thickness of the large washer.

It sounds like all I'll need to do is add a spacer between the front bush and the front mount, and I'll be good to go. I'll make it just slightly smaller than the gap to allow for a little flex in the control arm as the nut is tightened.

As for the alternative spacers - four of them went toward centering the lower end of the front shock in the lower control arm. I haven't figured out where the rest of them go yet. I'll need to fiddle about some more.

They might be used to position the inner rod ends off center, as you say, but they aren't matched to facilitate this. There doesn't appear to be a combination of spacers that equals the total thickness of the equally spaced set. If I substituted a thinner spacer to shift the rose joint off center, I'd need to make up the difference with washers on the opposite side. There is not a thicker spacer that closes the resulting gap. At least, I haven't found that combination, if it exists.

Thanks,

[JohnB_SPY8808053]

Just a thought - does anybody know if Gerry sells a replacement set of nylon bushes?

John B.

[rutthenut]

Originally posted by JohnB_SPY8808053
Just a thought - does anybody know if Gerry sells a replacement set of nylon bushes?

Yep, I had a set off him a few years ago - don't recall the price at all though.

Scott, you might also find that there are some extra bushes or 'sleeves' in the kit, as Gerry may have just put in a few of these 'just in case'. If so, they won't necessarily fit in any particular place without being turned down to your required length. But don't assume they are spares unless you are sure all other potential positions have been used up already!

[chris.richard]

Just in from the pub, so this might not be 100% sucessful!

Photos of my front mountings , as they were when i bought it - the lack mobility of the upper damper mounting looks a bit of a worry to me - should there be spacers there to stop the upper mounting moving on the bolt?

Front right upper mounting:-

[chris.richard]

looks like this:-

[rutthenut]

Originally posted by chris.richard
the mobility of the upper damper mounting looks a bit of a worry to me - should there be spacers there to stop the upper mounting moving on the bolt?

Yep, these should have been installed on the through-bolt.

The other thing that can make this is worse is that the shock runs at an angle in the fore-and-aft direction, which is increased if the suspension is set up to run a larger degree of camber.

This doesn't cause any real issues with shock travel or wheel geometry, but the Spax-type shocks (which you seem to have) are fitted with simple rubber+metal bushes at their mounting points and the inclined angle tends to try and force the shock eye off of the bush over time. The spacers on the through-bolt don't do anything to stop this, as they are of a diameter suitable for holding the inner bush in place.

If you have dampers with a rose-joint style of top mount (bottom too), then this problem goes away. The joint is designed to work more efficiently even when some extra angular loads are put into them and their design means that the mounting eye is unable to move relative to the mounting bolt.

So, I'd recommend dampers with a rose-joint style mounting, for this reason at least.

[mogul_x]

More questions I'm afraid.....

I was attempting to put the upper control arms on again, this time with all of the bushings, spacers, etc. in their correct locations. I ran into a small problem, and wanted to get opinions on the solution.

As I mentioned before, the upper control arm on my car fits best when the rearmost large washer is omitted. When I put the washer in, it shifts the whole assembly forward, which causes two problems:

1) there is a gap between the forward bushing and the frame (as already discussed in a previous post)

2) there is not enough room between the sleeves that straddle the shock upper mount to install the shock.

My car has a 34mm spacer to the rear of the shock, and a 7.5mm spacer to the front. This leaves a space of about 8.7mm between the two for installing the shock. The rose joint on the top of the shock is 12.7mm thick across the flats.

So, I need to find 4mm somewhere. My question is: where? Should I cut the 34mm spacer down to 30mm, cut the 7.5mm spacer to 3.5mm, or split the difference and remove 2mm from both? Are any of the proposed changes large enough to have a noticable effect on the suspension geometry?

Cutting down one or both spacers will allow fitment of the shock. To correct the other problem, I'll need to fabricate a pair of 3mm spacers to go between the rear surface of the forward upper control arm bushing and the front surface of the front mount on the frame.

As usual, any suggestions are welcome.

Thanks,

[colin artus]

You should aim for a vertical alignment of the damper or as close as you can get to it. This means that the spacers should be sized when you have adjusted the suspension for castor as this will pull the bottom control arm forward. When I fitted spacers on my car I made alloy ones necked down where they mate to the top rosejoint so that they bear on the spherical insert of the joint,
not on the housing.

Colin

[mogul_x]

All,

I have a question or two related to wishbone lengths.

A few Hawk owners have had problems with CV joints failing, caused by the CV joints bottoming out either at the top or bottom of the rear suspension travel. The solution, I believe, was to adjust the control arms so the CV joints didn't bottom out.

Anybody know a good way of setting the length of the arms to avoid this? Is there a particular minimum or maximum length to avoid when putting the rear suspension together?

Also, with respect to the lower control arms in general: Original Stratos and early Hawks had fixed length lower control arms (at the front for sure, possibly all four corners). Newer Hawks have rose jointed inners for greater adjustment. Anybody know what the length of the old style arms was? I'm trying to figure out how long to make the control arms on my car, and I figured the old lengths would be a good place to start.

The distance from the center of the inboard mount to the center of the lower ball joint hole, along a straight line, would be all I need.

Thanks,

[chris.richard]

Rather than alter the camber by lengthening the lower arm, you could machine 5mm off the length of the splines on the integrale CV joint without compromising the strength.

[mogul_x]

Chris,

Which splines are you referring to? The ones inside the CV joint where it's attached to the half shaft, or the ones that go into the hub?

Either way, I don't quite follow. Please elaborate.

Thanks,

[rutthenut]

Originally posted by chris.richard
Rather than alter the camber by lengthening the lower arm, you could machine 5mm off the length of the splines on the integrale CV joint without compromising the strength.

Chris, I'm not sure how this would help avoid the potential problem, as the outer CV joint is fixed into the hub and does not have any variation for end-float in that area.

The problem can be that as the wishbone travels through its arc, having a pivot point not the same as that of the inner CV joint, there needs to be come amount of 'plunge' available for the driveshaft. This is generally provided by the inner CV joint, which allow for the 'spider' to move in and out a small amount, as well as providing the angular motion required.

The driveshaft does not slide in or out of either CV joint on it's splined section, which would lead to potential wear. So if you were to modify the splined part it would make no difference in this case - at least from the way I read your message.

The other point is, for most, it's easier to adjust suspension arms than to machine parts of a driveshaft.

I also think that the point about changing the wishbone length is actually to set the desired camber angle, rather than causing problems with camber settings. If using the earlier, fixed-type wishbones then the camber angle is fixed by that and the position of the top mount. Fitting an adjustable top mount is a further option.

I can't provide the fitted length of my lower wishbones for comparison, because my hub carriers had been modified for further adjustment of camber angle, so any measurements will be incorrect for a standard hub carrier.

Hope that all makes some kind of sense.

[BAS]

[QUOTE]Originally posted by mogul_x
[B]All,

I have a question or two related to wishbone lengths.

I have just measured the length of the lower rear control arm on my 1989 HF 2000 GP4 (still being built) the distance between centres on this fixed lenght arm appears to be 282mm, hope this is of use!

[chris.richard]

Originally posted by mogul_x
Chris,



Either way, I don't quite follow. Please elaborate.



Judging from you response and John's posting, I think I'm the one missing something! I'll have to go and peer at the bits again. I was certainly thinking of the splined sections plunging and bottoming out - hence shortening them. I'll go back and read John R's article in Stratospheric about his CV joint problems.

[Steve_R]

Scott,

I had the same gap on my car and I just trimmed the washers and spacers to make it fit. Some of the chrome plating was flaking off the washers anyway, so I just got rid of all of it. I also had some binding with the front lateral links and the shocks ... just ground away the offending metal.

You didn't have a problem with the bar that the upper a-arm, etc. pivots on, did you? Both of mine were a couple of 0.001"s too big and had to be turned down to fit. The only other problem that I had with the suspension were the rear shocks. The top mounting hole was off by 1/4" or so ... now they're slots. I don't know if the uprights or the struts were drilled wrong, but it was easier to re-drill the struts.

I also reamed out all of the mounting holes, etc. which helped things tremendously.

-Steve

[roger001]

Originally posted by mogul_x
All,


The distance from the center of the inboard mount to the center of the lower ball joint hole, along a straight line, would be all I need.

,

I just happennned to have an old style lower front controll arm removed to fit a new balljoint, the measurement from the cetre of the inboard bush to the outer edge oft the ball joint "hole" (easier than measuring to the centre of a hole) is 370mm.

I hope this is of use, I'm sticking with non adjustable lower arms at the front but am switching to adjustable at the back to enable more accurate camber adjustment


Roger

[mogul_x]

Originally posted by Steve_R
You didn't have a problem with the bar that the upper a-arm, etc. pivots on, did you?

The only other problem that I had with the suspension were the rear shocks. The top mounting hole was off by 1/4" or so ... now they're slots.


Steve,

No problem with the upper A-Arm pivot bar on my car, apart from things being a little snug. I reamed out the holes in the chassis, and for the most part, that took care of the problem. I didn't remove any metal, just a surfeit of powder coating. No machining required, although the bar is still a little tight going through the bushes on the A-arm.

As for the spacers, I fixed the problem by machining down two of the spacers, and making four more. Gerry Hawkridge recommended splitting the difference, so the 34mm spacers became 32mm, and the 7.5mm spacers were replaced by new 5.5mm spacers. I added 3mm spacers between the front A-arm bushing and frame, and everything fits perfectly now. Once I align the front suspension, I'll see how the shock is oriented and decide whether further revisions are neccesary.

As for the rear struts - I had a similar problem, but a slightly different solution. I found that both holes were out of alignment on mine. To fix this, I ground the bottom inner edge off of the ears on the strut, which allowed the strut to sit lower on the hub carrier, and fixed the alignment problem with the holes.

The holes were still slightly misaligned, and would have required rework to accomidate metric hardware. One set of holes would need to be reamed, and the other slotted, if I used M12. Gerry mentioned that his uprights were designed around 7/16 hardware, so I used 7/16 UNF, and it went together with no further modification.

[mogul_x]

Brent, Roger,

Thanks for the measurements. That's exactly what Ineeded to know :D

Cheers,

[chris.richard]

Originally posted by chris.richard


I'll go back and read John R's article in Stratospheric about his CV joint problems.

One remedy mentioned in the above was to reduce the thickness of the driveshaft adaptor to prevent bottoming out on plunging. (say it with a straight face now). That's probably where I got machining something into my head.

[Steve_R]

Scott,

Glad to hear that you massaged everything into place. I too had to notch the struts, but I can't remember what size bolts I used ... all SAE, not metric. I had to ream out some metal on the lower control arms because it looked like the holes were drilled before the doubler plates were welded on and therefore weren't aligned. My pivot bar was oversized enough that it wouldn't fit through the A-arm bushes or the spherical bearing on the shock. No choice but to turn it down a little on a lathe.

-Steve