the BEST DIY rear cross member?

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Byron510
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RE: Re: RE: Re: RE: the BEST DIY rear cross member?

Postby Byron510 » 21 Nov 2006 18:29

I do have photos of the spherical bushes installed, but I'm currently traveling for work and am on the wrong side of the continent. I'll try to remember when I get home. The spherical bushes themselves are not that expensive (roughly $30 bucks each for a quality bush, crap is crap – don’t buy the cheapest, you get what you pay for – I like the quality of Aurora, NTN , there are a few others), but you need to have a sleeves machined up to locate the bush in it's correct location on the outer race. These sleeves are then tack welded into place to hold it all together in the control arm. Then a bolt (I use 5/8" bushes so I then use a very high quality - not grade 8 – 5/8” bolt) is used, again with machined washers of a cone shape locating on either side of the inner race of the bush, to make up the distance between the mounting ears. I have photos of a simple slotted rear end, and then a photo of one car which I did where the inner mount does both toe and camber correction, leaving the outer mounting ears standard.
Remind me in a week if I haven't posted the pics, I'll be home by then.
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defdes
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RE: Re: RE: Re: RE: the BEST DIY rear cross member?

Postby defdes » 21 Nov 2006 18:31

Oh, I'll remind you alright...just be glad I don't have your phone number.

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Postby Byron510 » 21 Nov 2006 19:02

No worries! :D

Most of this is just resource stuff. I've spent a lot of time reading over the years, then applying as much of it as I can to our old beloved machines. What can I say - I'm sick... and lovin' it.
Mike, concerning the rear X member bushes - if you are looking for a solid rear end from a performance point of view - I've done the following mod on most of my sedans: (if you are replacing a stock worn out bush and are after a nice quiet ride, disregard the following)

Remove (and drop to just below the mounting studs) the X-member onto a jack, pull off the large thin washer and rubber isolator (probably stuck to the body). Now replace the X member against the chassis using no washer or rubber. Concerning the two washers that were on the bottom side of the X-member mount, using the thick washer (call it washer A) that used to be under the lower formed "washer" (call this washer B). Place washer A onto the stud, invert washer B, place on stud so that the outside of the "cup now contacts the X member, (washer A is just taking up the space inside the cup against the steel inner bush), place a standard flat washer on next, and with a little Never-Seize on both the thread and the face between the nut and washer - crank it up tight until the center of the cup washer is hard up against the inner steel bushing. Your X member is now firmly in place, and this will eliminate some of the "rear steer" tendencies that are built into the car. I’ve always used a new nyloc nut – best source is your local Honda motorcycle shop as they have them in stock in the right fine thread pitch. This mod will be most notable when braking hard into a corner while slightly turning in - it helps under duress for you track type guys!
Byron

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Re: RE: Re: RE: Re: RE: the BEST DIY rear cross member?

Postby Baz » 22 Nov 2006 00:45

MikeY wrote:Baz, What to you use to replace the large bushings on the ends of the crossmember. The stock ones are no longer available here in Canada. Can you get them. I belive poly ones are available in the states but I woukld prefer something less harsh.


We use Noltec bushes they are more compliant than most.
will check on new nissan bushes for you.
If all else fails we have some Mint used ones removed from a low mileage granny spec.

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Rear X member LCA mounts

Postby Byron510 » 26 Nov 2006 10:07

defdes, I just got my photo resizing tool back in place on the new computer…

Here are some photos or a couple different styles of rear suspension mods that I've done. The Bronze car (orange stuff) was done by a previous owner; ears were replaced by new slotted plates. The charcoal suspension was done by myself for a friends car (Dan’s ’68). This unit does both camber and toe adjustments on the inner mount only, the outer mount had been left stock. I plan to build a few of these cross members this winter – one for the Bronze and two others for local club guys.
Hopefully this gives you a couple of good ideas for adjustment beyond the methods that are already out there.
Byron
Attachments
IMG_5699 (Small).JPG
Dan's Suspension0005 (Small).jpg
Dan's Suspension0002 (Small).jpg

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RE: Rear X member LCA mounts

Postby zootowndime » 28 Nov 2006 12:12

Hey Byron that is a really great idea for an adjustable crossmember. Do you think you would need to weld the bolts on after getting it aligned or does it stay put pretty well.
Also are you just using tow pieces of bent metal to make the brackets. Thats what it looks like. Possibly you wouldn't mind giving out some of the measurements you used. Or maybe even just make the brackets and sell them to me and i can just put them on.
Alex King
www.brewedmotors.com

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RE: Rear X member LCA mounts

Postby bertvorgon » 28 Nov 2006 13:27

We used the same idea, I have never had mine move.
Attachments
adjustable crossmember.JPG
Specialty Engineering did these, nothing ever slipped that I am aware of.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

Keith Law
1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
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Postby defdes » 28 Nov 2006 14:11

So, in review:
The top bolt on the top "tang" on the crossmember is just a thru-bolt thru the pivot plate (what is that, about 1/8" plate?), and just acts as the point from which to pivot the toe in adjusment slotted below on the bottom "tang", which is also thru bolted (7/16" hardened?). The camber is pretty self explanatory as its the same on every other slotted rear. The only thing I personally have a prolem with, is locking firm that camber adjustment. aftermarket busgings sit outside the steel sleeve in the rear swing arm, so you are trying to make a compression fit poly/steel which isn't a "positive" condition. I always have trouble loosing my adjustment, mostly on drivers side. Perhaps this could be helped by making a large fender style washer that compresses the bushing more evenly? Any ideas on that one?
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crossmember.jpg

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Postby Byron510 » 28 Nov 2006 23:38

defdes,
Yep, the top bolt is just a "hinge", but should be tightened after all toe adjustment has been made. , the bottom two bolts are 1/4 UNC socket HD cap screws - these were backed up with nuts also after final adjustment. On Dan’s set up, the stock rubber bushes were maintained, and the stock bolt was used. I would however, recommend that the rubber bush be replaced by a spherical bush at this juncture, to make the whole system a little less compliant. The idea is to take the rear steer out of the suspension under high loads. However, if no high loads are imposed, this isn't an issue.
As far as I know, Dan has not had any problems with this set up moving on him and it’s been installed for about 5 years now. This is why I designed this set up, as the generically slotted stock brackets were not adequate for me on my first solo car, the washers had to be welded into place to secure them (they moved twice on me, even after using the star type serrated lock washers). Tack welding the washers into place also works, but makes further adjustment a real pain in the arse down the road!!
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Postby defdes » 29 Nov 2006 07:12

The spherical bushings, are they a press fit into the opening of the trailing arm or attached some how? Are 8 total needed, (2 inner 2 outer each side?).

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Postby Byron510 » 29 Nov 2006 10:48

Only one bush per joint is required, so 4 bushes in total. They are a press fit (a little honing is usually required), then secured in place with sleeves - usually tack welded into place. Then a spacer need to be machined to take up the distance between in the inner race and the mounting ears on both sides of the bush, centering the arm in place. It's not that difficult, but does require some precision measuring and decent machining to make it right. I've seen the back yard approach just using tubing as spacers - it works, but why not do it right, and do it in stainless steel since it's exposed to all the elements under the car.
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Postby duke » 29 Nov 2006 10:55

Byron, I'm guessing that you have to remove the inner sleve from the control arm before installing the spherical bushings? What are the bushing dimensions...1 3/16" ODx5/8" ID?
Duke Schimmer

'72 2-Door 510
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defdes
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Postby defdes » 29 Nov 2006 11:11

Got any pics of one of these bushings, or maybe a McMaster-Carr link (are you familiar with this company?) http://www.mcmaster.com/

So the bushing/bearing is centered within the housing of what was where the original poly bushing went, then is held in the center by 2 equal machined spacers (solid bar with hole centerdrilled of eq. dia. of bolt and spherical bearing hole) and thats it. I would imagine with a good steel on steel (spacer to crossmember ear) mount, that I wouldnt have much slippage problem either. I would hate to tack them, because its on a race car and will need to be changed as needed.

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Postby Byron510 » 29 Nov 2006 12:56

The two outer sleeves would need to have some positive axial lock. I have tack welded them in the past. I did replace the ones on the Bronze last year - they'd been in place since 1972!!, and aside from being a little corroded, they were still working fine - hard to believe. Anyways, whomever dodo the original work on my car all those years ago also placed a small tack weld on each outer sleeve, and these placed no issues when it came time for me to replace them. However, there's no reason why you could not use a grub screw with a lock nut - say 5 or 6mm would work. After installing the bushing and sleeves on either side, using the correct tap drill side, drill and tap through the control arm and sleeve, place set screw and lock nut (use locktite while you are at it) and you should be set. There won't be much axial force on the part, but vibration is always the issue on suspension parts. Personally I like the little tack weld method – the tack doesn’t need to be big, 1/8” to 3/16” (2-3mm) long is plenty and very secure.
Duke, I use Com10 bearings for this job (10/16 = 5/8”). If the bore in the control arm is round (usually not) then you will have a .008" press fit -this is way to much! The hole in the control arm needs to be honed with a good hone, or reamed to a .000 - .001" press fit. You could even get away with a .001" oversize hole if you use a loctite bearing sealer, but I always like the mechanical fits without needing to rely on a filler substance. Installation should be done at .001" press fit, slightly warm up the control arm end (say 400 deg F) and the bushing will drop in. DO NOT use this method if you are planning to install PTFE (Teflon) lined bushes - disaster will result. Carefully press these in with the correct fit, using neversieze and a nice pressing tool that will only contact the outter race.

BTW – All this basic info holds true for the front LCA if you were wishing to do the same there. Same method - different size bush. On the front LCA, I use a metric sized bush for simplicity sake, but you could always sleeve the ID down to an imperial size. (Sorry, can’t remember the size off the top of my head, but if you are interested, just measure the thing! I’ll guess that is was a 38 or 40mm OD bush with a 19mm ID)
Byron
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Postby defdes » 06 Dec 2006 21:12

I posted this on another thread, but it went off on tangent, and this is the original place I was looking to post it anyway, sooooo..... this was the biggest hiem style joint i could find that would work with a 5/8" bolt, the outside diameter isnt big enough though, is it?
I couldnt post the page, so just cut and paste the part number in the "mcmaster search".
63215K38
http://www.mcmaster.com/


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