My trailing arm nuts keep coming loose. Guess I just need to replace them new ones or with nylon lock nuts. Anybody know the thread size off hand?

I don't know but I am now going to put that on my list of things to check. I get them pretty tight however. Poly bushings.

Common problem. I check mine after every race day.

GB

Mine get so tight sometimes I have to.....wait you mean trailing arm nuts?

Yea mine do get loose too. I think it has to do with after market bushings and the shaft. If the shaft and bushings are not centered in relation to the trailing are shaft tube you can't tighten the nut down until it seats at the bottom of the threads. I least that's what I'm thinkin'. Could be wrong.

When I was at Hershey this April the fellow from Air Cooled Racing showed me an improved trailing arm shaft. It looked to be a bit longer and stronger. Not sure how much they were.

GB

My theory is that the nuts loosen due to the shaft rotating.

I think the shaft rotates because the plastic bushings are too thick and don't allow the serrated ends of the shaft to 'bite' into the mounts like they should. I have faced the outer ends of my plastic bushings slightly to allow the ends of the shafts to contact the mount locations.

Anybody tried Loc-Tite - seems like a logical application? Mine are apart and I know I will have similar issues!

I agree with you. The end "flange" for lack of a better term on the bushings are too thick.

O.K. I have new delrin bushings installed and seems like I remember they stuck out a bit beyond the seration on the pivot rod end. At the time I figured knuckling down on the nut would be enough to catch the serations? Here's what it looked like;Click to view attachmentClick to view attachment

Pressing in the bushings. I used polycarbonate tube peices so I could see the
bushings seat;

I have the same problem.

Hopefully roller bearings will solve it.

Who's the roller bearing guy in the club? I know someone was working on it!

Does anyone know the thread size of the trailing arm nut off-hand. Help me avoid looking it up or measuring it.......

I hope you all know the reason for these nuts to come loose.

I promise you its due to chassis flex

Its a commone occurance on track cars.

you will someday go around a track corner and suddenly rip a CV apart (from stretching)

as you are wondering why or how that could of happened you will notice a big crack in your suspension console.

most likely the right side one.

I know this..
I lived it.
I used to tighen these (inboard and outboard) EVERY single track day for 8+ years

Then I ripped my console out.
replaced it with fresh.. brand new console.
continued tightening those nuts every single day for 6 more months.
then ripped out my 2nd console.

Thats when I learned about the need for a swing arm brace.
Haven't had a single swing arm nut come loose in the 10 years that I've used bracing. Even with 2 drivers doing wheel to wheel club racing.

I use bolt in bracing with aluminum bars.
doesn't weigh much.
comes out easily enough for dropping the motors.

the arm causes side to side flex at the console.
sometimes the console will oval out first
sometimes not..

eventually you will get to enjoy the same fun experience I have.
brant

Pictures please brant.

I have it come loose from driving about 4 blocks....

I think its a combination of a few things..

my -4 cylinder version is smaller and less intrusive.
but here is the basic idea:

I have had two real freaky occurances when the traing arm nuts loosened. I nailed it in a straight line and the car darted first to the right...then left...and I almost lost control of the car for about 1-2 seconds (long enough to do serious damage or die). I then checked everything and found that the inner trailng arm nuts were loose as a goose causing a sloppy toe in/out vasilation. It happened again just a week ago and the fu___g nuts were loose again! after red lock tight. I like the bearing idea...but I think I'll go to castle nuts and drill & pin the stupid things so they don't kill me. What are your collective thoughts on that idea. It certainly would put an end to the inners loosening...but I'm afraid I had better do both sides...

Bill

Ahh that piece brant.

I thought you have a piece that attached to the actual body, and then to the outside nut. Holding it from moving forward to back (getting rid of toe change)

Andrew.

I have the toe change brace too...
but that is not the reason your swing arm mounts are coming loose.

its the inner one that flexes and allow's the loosening....

look under the chassis some time.
the frame is straight down the longs.
but when it gets to the swingarm mount it turns sharply.

a TON of leverage is being applied (side to side) on that single bolt.
its the inner one that flexes....

by triangulating the inner one to the firewall you are adding LOTS of strength and bracing....

no one believes me... thats fine.
I like being faster and right.
wait until you have all dealt with a ripped console and then you will reconsider.

the nut comes loose from flex.

(10 years of reality testing proves it... Plus my guru has proven it on 15 other cars)

This is the only reason. We figured this out 20 years ago when we cut our first bushings. The serated ends HAVE to lock into the ear and the outer cup. If the bushings dont collaspe like the stock rubber when torquing the nuts down.. they will come loose. The shaft is NOT designed to pivot in the mounts.

That being said: I shave all the plasic bushings until the serrated ends hang past the bushings. Problem solved.

You should still check them AND the inner mount every event. Also make sure your drains are clean on the bottom of the inside mount.


B

pretty much what Brad said....

for the roller bearings, the shaft sticks out past the trust washer by about .001" to .002" per side

yay!

See ya tomorrow Mike!

I'll let you guys know if the roller bearings loosten up on me. Doubtful.. but it would prove brads point (not like it needs to be proven)

They wont come loose.

There is NO drag on the shaft with the roller bearings like you get with the plastic bushings.

I checked them before every event on the first car we did back in 02 or so.



B

Cool beans..

YOu also stated that it loosens up the suspension a bit? making the ride less harsh..

so.. my 275 lb springs will feel like 250 or 240 lb springs?

just curious.. (the 275 lb springs felt fine though...)

The rubber bushings have "spring" in them amounting to something like 20lbs. The plastic bushings have "stiction" that is imeasureable (infinite spring rate)

Roller bearings: have NO effect on the overall spring rate. No drag.

The car will ride smoother than it did with the rubber bushings. The shocks now work and valving becomes more important. The shocks will not fight the "stiction" in the system.

Ever heard a 914 or 911 "creak" while going past you at a AutoX? Every time you hear it creak.. it is the suspension sticking.

Push down on the fender of a plastic bushing car and count how long it takes for it to "jounce" back. Some take several minutes. Do this with a roller bearing car and the car will follow your hand up and down.


B

Basically.. your saying this will go with everything I have with my car and transform it..

Its the "missing link"

275lb rear springs, koni yellows, nascar 1 1/4in to 3/4in front sway bar, 22mm T bars, T Trods and all the little stuff..



Goodie!

I was reading elephant racing's opinon on the roller bearings and it seams that they might not be able to handle a whole lot of load.. Would it be a good idea to run true slicks on it? They are in my plans.. I assume R tires are fine..

Andrew

Chuck isnt an engineer.

The bearings used in the kits are WAY overkill for the loads we can generate.

Throw all the engineers you want at it. We have real world sucess stories with street cars and race cars. The bearing kits have been around since 1998. If there was a HUGE scary problem with failures.. we would have heard about it 100's of times by now.

I even pulled apart one of the first kits to inspect it... I found NO wear on the bearings or the "race". I cleaned them up and set them side by side with a new bearing.. I couldnt tell the difference.


B

Thanks Brad, I knew I wasn't imagining things for the last 18 years of working on and driving the crap out of these little cars.

However, Brandt has a point. Those ears are weak and will eventually tear loose given enough time and sticky tires.... I'm adding them when I flare my car and put larger wheels/tires on it.

I have no worries..

Sweet. Im going to bed.. Gona help Mike out around the house, and he's gona help me install those sweet pieces!! Hopefully i'll be running by sunday! (maybe... maybe not.. lol)

Brad

While racing at Mosport this past weekend I had this very problem happen. The trailing arms were creaking and started to bind up and made handling rather interesting. I put new urethane bushings in over the winter and after 2 events they're already starting to bind. Brad do you sell the roller bearing kit and how much?

Thanks Gord B