Visit The Dirt Forum for More Information

Author Topic:   Best Way to Free Up Trailing Arms is?
RC Racing
Member
posted February 18, 2003 12:15 AM
Read an earlier post that dealt with the best waay to set up trailing arms. I've attempted to adopt one of the suggested methods so as to free up the rear end. I've welded washers in place. Then proceeded to secure with 2 jam nuts. Came across what I think might be a potential problem: they're doesn't appear to be enough bolt threads showing/extending past the outermost (2nd) jam nut when I'm finished. (an old experienced A&P , that's an Aircraft & Powerplant mechanic, once told me I should always have at least 3 threads showing) And I don't want to tighten the 1st nut anymore, or I'm defeating the purpose of the whole excersise (tightening adds bind).
So what I'm wondering is:
1) where can I get slightly (maybe 1/2") longer bolts. The original ones have a shuolder machined into them starting just below the hex head. You know, stock GM a-arm bolts.
2) Can I get away with just using a locking nut? not the type with the nylon insert, the nylon might/would give, but the solid metal ones with a taper
3) Other ideas?

Thanks all

------------------


Big Dawg
Member
posted February 18, 2003 07:42 AM
I,drill all of my trailing arms and upper and lower a-arms out to a 1/2".I'f you use stock bushings you will have to drill through them also,if you use the racing neoprene bushings a 1/2" bolt already fits through most of them.I always use a locknut with the plastic,and never had one come loose.


istock59
Member
posted February 18, 2003 08:56 AM
Ditto what Big Dawg said. I always redrill mine out to 1/2". Front and Back. None of that metric bolt BS for me.

And I like to use Grade 8 bolts, 1/2" UNF thread, with metal locknuts. If you're looking for a place to order online, try www.mcmaster.com.


RC Racing
Member
posted February 18, 2003 09:33 AM
Thanks guys. And I'm with you ISTOCK. Hate this "Which tool do I pick up: Metric or SAE?"

------------------


powerglides
Member
posted February 18, 2003 10:52 AM
Hey Powerglides, I like that idea a lot! Maybe on the next new car tho. Kinda hard to get into some of them spots now.

You know tho, if somebody made a 1/2" bolt that was designed just like a brake caliper bolt... ;P

c21
Member
posted February 18, 2003 01:42 PM
Yeah c21, should have mentioned that too. Used plenty of NAPA anti-seize on all mine. Bolts seem to hold up fine, as do the washered holes. Have had to replace the urethane bushings on the RF a-arm on occasion tho, so that's something I inspect every winter.

FWIW...

RC Racing
Member
posted February 19, 2003 09:42 AM
C21, appreciate the "engineering" viewpoint. I tend/try to look at issues in much the same manner, but unfortunately I'm a EE, not ME.

Anyway, now that you've pointed out the potential problem(s), what is the solution?
1)Coat surface between frame & bushing with a good silicon spray before every weekend
2)Keep close eye on bushing condition
3)Other suggestions for free/non-binding travel

Points to consider: 2300# car, rules state we must use unaltered trailing arm with stock bushings

Thanks

------------------


powerglides
Member
posted February 19, 2003 09:50 AM
Heck powerglides, BYE's usually possess the best training and skillset: it's called "Common Sense"

Take care

------------------


d4490
Member
posted February 19, 2003 10:31 AM
I don't know if anyone has seen these, the Mono-Ball bushings used in the front lower a-arms. They use a shpherical rod bearing in a housing that welds into the lower a-arms. I have seen a company that makes these for the rear suspension, used on the 79-93 mustang (4 bar, metric style). I called the company and asked if you needed a panhard bar with these, and the said that the bushing hold the rear end location (side to side) tighter than the rubber or poly bushings, while giving you free motion in all other directions. Almost no bind.

I plan on making some on my lathe in my shop. I will let every one know how they work.

RC Racing
Member
posted February 19, 2003 10:36 AM
Wish I could use those (DCA in Wisconsin sells them). Unfortunately our rules state: STOCK bushings

------------------


c21
Member
posted February 19, 2003 12:01 PM
Just a point on "lock nuts". My opinion is not to use nylon lock nuts on any suspension bolts. If you need a true lock nut, use an oval lock nut. You can get them at any bolt supply store or www.mcmastercarr.com. These will not come loose, if you really want, use loctite with them. The one problem with oval nuts is it will damage the threads on the bolt if removed and re-installed too often. And as far as lockwashers, well I NEVER use them, I don't want to take the time to explain why.

This knowledge comes from industrial maintenance (15 years) as well as racing.

Randy

powerglides
Member
posted February 19, 2003 05:01 PM
C21, took some measurements of the bushings with the mic. Should be pretty close:
1) overall length of the inner sleeve (looks like a piece of flat steel rolled into a tube. ie, it's spilt, not a solid piece of material): approx 2.40" +/-.05
2) I.D. of sleeve 0.525" +/-.05
3) sleeve thickness: 0.125 +/-.05

The bushing, as you know, is not a high tech piece of equipment, so GM's tolerance from 1 bushing to another was, should I say, loose.

I'll call Thomson Industries and request a couple different sizes and configurations of the nyliners. Will keep everyone informed, via this post, as to what turns out.

------------------


c21
Member
posted February 24, 2003 12:27 PM
Just welded nuts on about 3 weeks ago everything went easy on mine I didn't have to drill anything or put bigger bolts in.The big difference is I'm running a 77 ltdII and there where 6 9/16 bolt and 2 1/2 inch bolts on the arms .I welded nuts on lubed the grage 8 bolts put them in,tightened until just felt alittle drag on the arms double nutted done deal. I will just have to check and maintain thru the year.


RC Racing
Member
posted February 24, 2003 01:24 PM
Appreciate you staying with this one C21. And if we come up with something, I suggest we go for a patent (half kidding). Why? At playday yesterday, discussed what I'm trying to do with a few guys in this class. They were keenly interested. One noted that when he did NOT properly tighten the frame mounts to the trailing arm (left it loose enough for the arms to move freely) he almost tore the arm out of the car.

Spoke with Thomson today and they're sending me some samples.

I plan to either: mull over the options you've presented today (I like the ideas listed in #s 2, 3,4, & 5 below. I've already welded washers in place on both sides of the arm's contact areas. And instead of welded nut, using jam nuts.)

or: decide on the bearing of choice, after looking at the samples and then maybe go with our first scenario.

If I choose to go the route of the origianl concept (using a Thomson #8L12-FK-642 or similar bearing), assuming I get through the 1st time out ok, I'll remove and throughy examine the modified area post race. And if all appears ok, take it 1 race at a time, with inspections after each race. AND, I'll probably replace the bearing about every 3 or 4 or x numbers of races.

------------------


RC Racing
Member
posted February 24, 2003 01:27 PM
Should have said "2,3,4, and 5 of C21's note".


Dirtracer7, is your rear end assembly (on a Ford right?) similar to those on a GM metric?

------------------


c21
Member
posted February 24, 2003 02:09 PM
RC,

If the track on race day is like it was yesterday I would tighten the bolts as tight as you can get them, after a couple laps everything will be loosen up. They will probably throw a caution so you can get out and check everything. Where those ruts or ramps?
Let me know what you find out about those liners.


teamstertom
Member
posted February 24, 2003 04:54 PM
My buddy who built a new Wissota legal super stock has the DCS bushings in place,and do they make a believer out of me. This set up is a sure answer to freeing uo that rear end. There are a couple of guys that are running these bushings in 3400# 73 Monte Carlos with big blocks and a turbo 350 on 1/4 dirt doing real well. If you can run these things,I suggest doing it. I think for somewhere around $200 you can do the 4 bars.


RC Racing
Member
posted February 24, 2003 07:08 PM
Hey Deed. Yea it was starting to look like y'all were runnin the Baja. Now you know why I'm not in a big hurry to put my car on the track. I'll let y'all work out the kinks (or should I say ruts and jumps) out of the track 1st. Chris said he needed that time with cars on the track to find the bad spots. Maybe he should reimburse y'all for the ball joints you're going to have to replace.

------------------


Darcy
Member
posted February 24, 2003 07:08 PM
RC to cut this short all you have to do is use nylon bushes on the bottom arms and standard on the top it stops the bind and keeps you rear inline it works i have been doing it for years
Regards
Darcy


RC Racing
Member
posted February 24, 2003 07:14 PM
teamstertom: appreciate the info on the DCA units (I've purchased some stuff from them recently. Good quality, little steep on $s though, but you paty for one to get the other)

But to you and the others that have replied suggesting other than stock... guess I've got to see how far from the rules ("stock bushings") I want to risk. Keep those cards & letters... I mean suggestions coming in though

------------------


dirtracer7
Member
posted February 25, 2003 10:52 AM
RC it is similar but my upper arms don,t mount near the centersection like a GM .The 2 upper arms mount out near the backing plates and the lower arms are mounted inward of the uppers this on the axle end.The newer cr vics 79 and up are similar to your GM setup.


racinrich1
Member
posted February 26, 2003 08:28 PM
Darcy,
Have you found...having the lowers extra flexable alows them to follow the uppers without binding? Do you run the stock rubber bushings on top?
Rich


Back to the Archives