I fear my right rear suspention ear has been ovaled due to rubbing of the trailing arm shaft and the ear. With the rear jacked up I can move the wheel back and forth. Not much, but I see the trailing arm moving at the ear. I want to catch this before it gets more serious. How much would it cost to fix the ear hole? Is this something I can do in my garage, or should I let the pro's do it? I "might" have access to a welder, but I dont have access to experience.... :toilet:

The oval shape is supposed to be there, Chris. Part of the autochamber adjusting feature if I remember correctly.

I can bring my MIG welder and mini grinder but you are going to have to find a ream the right size for the hole. Try Hardwicks off Roosevelt Ave and 42 ave NE as they seem to have damn near everything else.
Did you squeeze Dave's 914 into the other bay in your garage? If I drag my welder around I want to do the passenger floor pan at the same time on his car. Where are you buying me dinner at if I come over?

I got one week left......free.

Geoff

If it is supposed to be oval, why is there movement at the nut and shaft? Dave's car is not here yet. I am cleaning out the garage this weekend, so sometime next week it will be there. If your girlfriend comes home before the welding gets done, maybe you can sneak out... -style
You like burrito's? Taqueria Guymas in West Seattle junction is awsome. Carne Asada burrito, a Pacifico cervesa, a side of fresh salsa verde.....

Well, my dad finally caved. I moved the 914 today. Found out, my dad is cleaning out our garage for me , and the Porsche goes in there soon.

Thanks again, Chris. I think your generosity has made my dad second guess his actions

Hey, if I have to drag the welder to Fremont to weld your floor you gonna buy dinner from Pesao that Carribean place??
Food is what gets me to do stuff.....
Geoff

One thing I've heard of people doing in this circumstance is welding a hardened washer over the now-ovaled hole. I don't recall if the hole in the washer is then reamed to size, or if it is left as-is.

--DD

Thanks for the tip Dave.

The washer ends up not allowing your "lock nut" to lock. Not enough threads. The only people doing this are the ones who dont fix it correctly by welding it up and reaming it to size. The nut has its locking portion at the very end of the nut. You would end up with a rounded out washer in a few months.

B

Lock-tite!!! Thats what we did on mine, for the tow. Might only be temp.

The "proper" way to fix it is to weld the hole and re-drill it. See the two pics below. This is what happens when you have 400ftlbs of torque and improperly installed poly bushings!

before



and after



-Tony

Tony (in my redneck dialec) what kind a shiny heat exchangers are those next to the warbled out hole ?? Them there sure is pretty.

I'm leaving tomorrow at 9:30 am.

B

Them there's are the Hooker Header heat exchangers!

I will try and be there by 9:30 to give you the 993 stuff, give or take a few Starbucks minutes.

-TC

Looks like you need to git reamed, Chris....lots of fun welding that kind of stuff too and the grinding is the good part!
Better start lookin for that ream! I don't think I wanna try drilling that out with a Hole Hawg as it looks like a knuckle buster.
Geoff

A Unibit works great, it is nice and short and will provide a nice clean, burr free hole.

-Tony

Thanks Tony!

Geoff

so, how does one install poly bushings incorrectly that makes this happen?

-Tony

who is now parinoid after installing his new poly bushings

The poly bushings are too long and do not allow the center rod to bottom out on the mounting ear. Without the center rod bottoming out it allows the trailing arm to move around under force. The fix when installing the bushings is to grind/shave/file a little off each end of the OUTSIDE of the bushings. Don't over do it though, just enough that it bottoms out.

-Tony

damn...and I just thought I was almost done...

I noticed that when installing them in the control arm, but I thought it would compress in when I mounted the arms to the car ...

oh well...whats another night in the garage

Thanks,

Tony

If you don't trim the ends of the bushings to fit properly, it will negate any improvement from running the hard bushings. Not only will it ruin the mounting ear, but the trailing arm will bind, badly. The polygraphite is not compressible!

So how much are you talking to trim off the bushing??

Geoff
Still working on putting the front back together

In order to get the bushing installation right, it is necessary to press the bushings into the arm. Then slide the shaft through until one end is flush with the end of the bushing. The difference from the end of the shaft to the end of the bushing at the other end is the total amount you have to trim off the bushings.
Usually the bushings don't fit well into the arm. They should require firm hand pressure to install. The shaft should slide through with little effort. Normally the bushing becomes out-of-round when it is pressed in the arm, and this causes the shaft to bind. Also the two ends are usually not on a common center, so even if the shaft doesn't bind in either bushing, it will when it is in both.
Monoballs eliminate the problem entirely, but require a lot of modification. Roller bearing kits are better than the Weltmeister polygraphite bushings, but they are expensive and have their own shortcomings. My Delrin bushing installation completely eliminates the binding problem. I also address the common problem of rust on the pivot shaft by grinding the shaft to a slightly smaller dimension.

I made the bushings fit like you describe...firm to press in, but where the center shaft slides in easily...and that did take a while...but I didn't know about them being too long and not allowing the shaft to bottom out...so I am going to yank them back off and trim down the faces. Glad I found this out before I went for an alignment...

Chris, I don't know anything about derlin...what is special about it itself...and what is so unique about your installation? not trying to attack, I am just curious...maybe a good option for me on the second time around doing this (which I expect will be at the end of this year).

Thanks for the help,

Tony

Delrin is a hard (usually black) plastic, much better suited for suspension bushing material than Teflon, Nylon, Poyurethane, etc. It is of a higher quality than the polygraphite bushing material and it will last longer. The polygraphite is molded, while the Delrin must be turned on a lathe.
I prepare the trailing arm by reaming the hole accurately, so my bushings press in with the right pressure and they are aligned to one another. That way the shaft, which I have ground slightly to provide a fresh smooth surface, fits without binding. I also add grease zerks to the trailing arm to lubricate the bushings, and trim the end of the bushings to fit the shaft precisely. I have seen some variation in length of the shaft, as well as the trailing arm, so there is no "one size fits all" solution.

I'm going to shoot two short video's tomorrow of the roller bearings installed on a FP car. I will "work" them by hand to show the lack of drag. Something insteresting that is being missed in this thread: Your plastic bushings can be reamed/trimmed/polished.. whatever and they can spin freely while testing them on the bench. The problem is: all this changes when the weight of the car is on the bushings. Today, Tony and I where taking a look at Bontempi's FP car trying to find a measuring point for the trailing arms....Tony pushed down on the left rear of the car (I had this apart less than 3months ago and it moved freely) the car took about 30+ seconds to rebound from his "jounce". NOW, our roller bearing cars move up and down with a "jounce". I promise a well installed and greased plastic bushing has more drag than any of the roller bearing cars. I know the roller bearings are not really designed for "Joe Blows" street car.

B

Also another thing to remember is that when loaded (ie in a turn) delrin and Poly have HUGE amounts of stiction/friction. This is where roller bearing or spherical bearing REALLY come into play.

A side note on the spherical bearing set up, the link that someone posted to the PP board shows Armando's spherical bearing set-up, please be advised that this set up for me, or another fabricator to create will be $2000+. The roller bearing set-up that Mike M/Tony/Brad are working on will be less than $500 and WILL address the problem of lining up the shaft square with the innear pick-up point. Stay tuned for more information.

-Tony