What do you think of my sway bar mount

Jeff Higgins · 01-27-2005, 03:51 PM

I fashioned this in lieu of the old style cup over ball mount on my '72. What you're looking at is the original lower mount with the cup cut off, the web that supported it notched all the way down, and a deep union nut welded into the center of the notch. A very long allen head set screw joins it to the clevis above. It's adjustable for length, but since neither end is reverse thread, I have to pop it off to do it. This whole thing is bolted to a heim joint that I attached to the control arm. I drilled through the dimple where the ball normally welds on and simply through-bolted it. The whole works seems to work pretty freely with no binding, and it will never pop off the ball. It does hang a bit lower than stock (I wish I could find a shorter clevis) but that doesn't seem to be a problem. So, any comments or suggestions? Does it look reasonable, or did I miss anything?

widebody911 · widebody911's Garage

Damn, that's pretty industrial-stength!

You know what would have been cool? Use a shorter U-joint and/or some "unused" threads so you could adjust the preload.

911pcars · 01-27-2005, 09:20 PM

Looks good. I think I've seen some steel clevis joints with a shorter throat area. Might provide some room to expose some thread or increase the ground clearance.

The following doesn't apply since you only have a single-thread drop link, but drop links with right and left hand threads on either end are overrated. If there's any tension on a drop link from unequal ride height or preload, you don't necessarily know what direction to rotate the Left/Right-threaded drop link to get it to a neutral position. So you end up removing it anyway; remove the rod bolt, rotate the L/R-threaded drop link one way or the other to line up with the mount holes, then reinstall the rod bolt - all with the suspension at regular ride height. With the rod end removed, it really doesn't matter if the drop link ends are L-R threaded or not.

Sherwood

Jeff Higgins · 08:44 AM

I'm still looking for a shorter throat depth on a clevis, Sherwood. I know they are out there, I just haven't found one yet. In the end I may just wind up making one. I was in kind of a hurry to get this one and try it out so I used some stuff I could find locally. I can see this going through a couple of iterations as I fine tune the idea; that's a lot of the fun for me. I have to kind of agree on the thread problem; to set it up the first time I set both ends so the bolt through the clevis and heim joint went in with no resistance. Without being able to gauge pre-load in some similar manner, it seems I could innadvertantly pre-load one side and never know it. I don't know that much about adjusting sway bars anyway. What exactly are you adjusting for when adjusting a sway bar, anyway? Is there any case where you would want one side pre-loaded in one direction?

911pcars · 01-29-2005, 12:26 AM

Jeff,
Preloading one side of the axle can cause the vehicle to handle differently left and right due to a higher spring rate from the added influence of the sway bar.

An adjustable link is a good idea to remove any preload the sway bar may have on the chassis. This happens sometimes when the chassis is weight balanced and the corners end up at slightly different ride heights. Please note that you only need one adjustable drop link per axle.

Adjustable drop linnks are not essential for "normal" driving. I know of no factory vehicle with adjustable drop links. However, you can feel the difference when a car is properly weight balanced, i.e. the left and right side of the vehicle has the same front/rear weight proportion. The car will track straighter and handle better, and since all corners share the same proportionate load, braking will be more consistent.

Sherwood

exhaustfumes · 01-29-2005, 04:52 AM

mcmaster-carr has a huge selection of clevis's. they are online. i used them to build a brake pushrod linkage for my streetrod.

joe
77 911
48 willys wagon streetrod

doozer · doozer's Garage

http://www.qa1.net

makaio · 01-29-2005, 08:14 AM

Looks good! As a preventative measure, if you haven't already reinforced your sway bar brackets, you should do so.

Jeff Higgins · 01-29-2005, 08:44 AM

My car didn't actually have the welded-on brackets, Matt. After hearing about some trouble with them I decided to use the Weltmeister kit that clamps around the torsion bar tubes. They seem quite well made and are pretty darn simple to install. Thanks for the Mcmaster-Carr link guys; it looks like they might be the ticket. Thanks for the set-up information Sherwood; that's what seemed to make sense as I was installing mine.

911pcars · 01-29-2005, 10:56 AM

Jeff,
I might add that all the manufacturers of rod ends also make clevis joints (Aurora, FK, QA-1, Alinibal, etc.).

Besides McMaster, there's Racer Wholesale, Pegasus Racing, Aircraft-Spruce, Wicks Aircraft Supply and Maryland Metrics to name just a few.

I'd also suggest a stronger steel clevis to replace the cast piece you're using now.

Sherwood

kucharskimb · 01-29-2005, 04:53 PM

jeff
can i see a pic of the clamp on mounts. maybe a worm's view picture...

thanks
matt

Jeff Higgins · 01-30-2005, 03:44 PM

Quote:

Originally posted by kucharskimb
jeff
can i see a pic of the clamp on mounts. maybe a worm's view picture...

thanks
matt

O.k., I'll crawl under and get one in the next day or so.

Elombard · 01-30-2005, 04:29 PM

Yes I have not heard of the T bar clamp on mounts, sounds like a great solution!

Jeff Higgins · 01-30-2005, 05:49 PM

O.k.; here are a couple of photos of the Weltmeister torsion bar tube mount. I bought mine from our host. Pelican's part number is SB-2900. They don't have a photo, but the Weltmeiser web page does. I hope this helps. I found them to be a snap to install with some very clear and simple instructions included. You will notice I used a couple of shims (included in the kit) to lower the bar a bit. Mine was riding on the transmission mount, which I guess is not uncommon. Just watch for that, and make sure the bar rotates freely without rubbing and you're set.

kucharskimb · 01-30-2005, 07:40 PM

jeff
thanks for the pics. looks like you might want 5mm longer bolts for the bushing brackets. the threads don't look like they are protruding through the nylon lock nut after adding the spacers...

any issues with the bar winding up since the brackets are inboard of the drop links by a few inches? (moment arm plus a vertical force with the bracket acting as the flucrum for both?)

matt

Jeff Higgins · 01-31-2005, 05:01 AM

I was looking at the bolts as I was crawling around snapping the photos. I arrived at the same conclusion; I wonder why I didn't notice that before. As far as the bar winding up , I'm not sure how I would tell if it did. The clamp-on brackets are about six inches inboard from where the welded on ones would be, which mount just about out to the bend in the bar. The right hand mount could be placed much further outboard on the torsion bar tube, but the left one is limited by the fuel pump. I wanted both sides the same so I placed the right one at the same distance from the car's centerline as the left, which is all the way out to almost touching the pump. I do see other makes of cars with the frame mounts much further inboard than this, but without knowing their bar diameters, spring rates, and other pertinant data, it's hard to say if they would exhibit more or less of a bending moment on the bar than this set-up. It is pretty clear that in this installation the bending moment on the bar is greater than if it were supported on the ends. If it is enough to make a difference in how it functions or how the car handles, I'm not sure. Good question. I did run the car for almost a year without front or rear bars, and then for about a month with a front only. This gave me the chance to really feel the difference the addition of first the front and then the rear bars made; the difference was very noticable with both installations. So even if the rear loses a little effectiveness to the mount location, I don't think it is very much.