Airbar rear question in 69 camaro

[Munster]

I'm in the process of installing my Moser rear from Frank at Prodigy into my airbar rear set up on a 69 Camaro. New install for all parts. Rear axel is a 12 bolt with tabs for airbar prewelded at moser.

I think I need the measurement from the top of the axel tube to the bottom of the frame rail directly above the tube. The instuctions say to cut a spacer and tack weld in place(when getting ready to tack tabs to the axel) to get ride height established but I can't use that measurement because where you are supposed to tack them in was removed when the mini tubs were put in. Their pictures show it on a non tubbed car.

My problem is when I put the axel near what I think is, or is near, ride height, then in order to get the pinion angle set I would have to unscrew the adjustable end of the top link out so far I don't think there will be but a few threads left in the threaded area of the upper link shaft. Is there more than one length of upper link? I might have something wrong but it seems my upper link is to short. Could my welded on tabs be off a bit? Just by comparing the pics in the instuctions to my tabs, mine seem to be back to the rear more. (please, please don't tell me this is screwed up) The instuctions say that the upper link should of started with an 9 1/4" center to center measurement and that appears way to short.



Any help especially from the ART guys or Frank would be appreciated.

[Vegas69]

Get the lower bars intalled and put the rear end on jackstands without the shocks and springs. Install your wheels and put it right where you want it. Measure your drivetrain angle off the harmonic balancer or the ujoint out of the tail shaft of the transmission. The rear end should be .5-1 degree down from the driveline angle but opposite. For example my setup.

Drivetrain angle 4 degrees down
Pinion angle 3.5 up

My wheels are centered in the wheel wells and no rear end vibration with my GBAR.

[JRouche]

Ok, Im a lil lost on the spacer idea. Thats just me, not your description.

I have a art morrison 4-link in place already so prolly not much help. I had the axle set at the proper angle for the pinion angle and bar setting. Lower bar is parallel to horizontal for ride height. Upper bar has a slight downward stance, pointing down to the front. I had my art morrison coilovers at ride height and made upper shockwave mounts to the frame by measuring up from the axle mounts I made. Mine (shockwaves) are 14.56" center to center. So after the axle mounts were in place I measured up and tacked in the upper mounts.

To do this I made some solid struts, with the exact eye to eye distance that the shockwaves were going to be at. I didnt wanna be welding around the rubber bladders. So with the lower side of the strut firmly bolted in place on the axle and the upper mount attached I welded it to the frame. Its a solid mount now, and even on both sides.

And I still have the solid struts in place as I am welding the watts link in place. With the struts being solid I am sure it places the axle in the proper alignment for the watts link (pan hard bar still in place for lateral placement). The whole car is on the struts.

For your pinion angle, I cant really see if the upper bar placement is to far back on the axle. I would have to be there. It looks a lil bit tilted back. On most four bars I have seen they still have the eyes for the lower and upper in a similar vertical alignment. Yours looks like the upper eyes are tilted way back?? But its not a parallel four bar right? A triangulated four bar. So the upper eyes may be back from the lowers.

But whatever the case, you are right, you should have more than a few threads holding the bars in. Can you scoot the lower bars in more (with the threads) to gain some threads on the uppers while still keeping the proper pinion angle.

Really, thats the only reason I went with a 4-link, for pinion adjustability during my build. If I knew the proper angle I needed I would not have needed to go with the 4-link. Kinda bassakwards but it works for me. JR

[darren@ridetech]

What do you have pinion angle set at? What angle is the tranny/motor at?

[ProdigyCustoms]

Call me, Looks like your pinion angle is up right now best I can tell. Looks like the front of your car is down, the rear is in the air, and you have the rear level, which would be up a ton. The car needs to be level. -.5 would be perfect and adjust from there.

The brackets are jig welded and we sold 47 rears last year. BUT, they are built by humans also.

[Vegas69]

Since I'm such a nice guy.....I found that one full turn on the upper bars netted a 1/2 degree pinion angle change. I'd get the car as level as possible next. You can level the car off the rocker panel. It doesn't have to be perfect but you need it on 4 jack stands.

[Munster]

The car is nose down, yes, so I'm going off the dampner. It reads about 3 1/2 degrees. The pinion face on the rear is about 10 degrees. The angle finder gauge is gravity based so since the motor is fully bolted in and trany on the nose down angle should not be a factor. They are both realevent to each other as long as the rear is at ride height and the motort/tran are bolted solid. I need to find a measurement so I can place the rear close to a known ride height instead of my guessing. I looked at the instuctions close and the thepic of the spacer tacked in looks like I could place it on the inside of the frame rail and be within 1/2" or so. So I will try that, but it still looks like when I pull the pinion nose of the rear up to match the angle of the motor I will still have to thread the adjustable eye of the top link out, either to none or very little threads still engaged in the link. How much thread should you be looking for? I think it should at least be 1/2" or better thread to thread contact. I have to take my daughter to the airport so it will be tomarrow before I can check again.

[Munster]

Call me, Looks like your pinion angle is up right now best I can tell. Looks like the front of your car is down, the rear is in the air, and you have the rear level, which would be up a ton. The car needs to be level. -.5 would be perfect and adjust from there.

The brackets are jig welded and we sold 47 rears last year. BUT, they are built by humans also.

Frank I don't even know if I have a problem yet. Usually it is just me being a dumb a$$. I just want to get the ride height nailed so I can take that factor out. I will call first chance I get. Just a busy time for me with all thats going on here.

The nose(of car) is down but the rear end is pointing toward the ground quiet a bit not level.

[dhutton]

Check your eye to eye measurement for the shock. It should be 14.5 to 15 inches at ride height.

[darren@ridetech]

Check your eye to eye measurement for the shock. It should be 14.5 to 15 inches at ride height.

Frank, do you know which holes the lower mount should be bolted to on that axle?

[JRouche]

Just a lil more info. I built my mounts while the rear was way up in the air and the front on the ground. I have a SPI digital protractor (cheap). Whats really nice about them is you can take a measurement, say yer looking for vertical. I take a frame reading that I know is vertical for the car and I can now take that anywhere on the car, even when its on an incline, its a relative number, and get vertical. Works great for pinion angles. Shoot the block face then the pinion face, compare the two, it does it for you. Even shoot the drive shaft and compare the actual pinion angle and drive shaft angle. Shoot the frame on a horizontal and then the drive shaft, gives you your drive shaft angle. Looking for offset angles side to side, say you want a mirror image of a link from drivers side to pass? Simple, just rotate the protractor. I wish I had the digital protractor years ago. And the next task for it is gonna be front end alignment. Yeah, camber readings are gonna be a snap now. Indispensable tool. JR

[Munster]

Ok, Im back. Thanks for the replys. Went to the garage today and set up my car using the 14 1/2" to 15" distance for the shock mounts center to center. So with bottom links hooked up, axle at ride height, shock eye distance 14 3/4" exact on both, top bars loose not attached, pinion angle set to match front harmonic pulley at 92 degrees equals the following.... top link mounting holes then have a center to center measuement for lenght of 10 1/4". Which is 1" over the 9 1/4" they are supposed to be set at not to mention that the top links will not go to 10 1/4". At this point I called Frank at Prodigy, who thankfully is a great guy, and let him know I have checked and double checked and tried to rule out all errors, what I have which appears to be the top link brackets welded to far back, he said he could make up a set of longer upper links and send them out, and I thought problem solved till I went back out to the garage. And put my rear wheels on with the rear axel, which is still set up on stands and blocked to simulate the longer links in place. And found a problem, since the lower link is a fixed attaching point near the bottom of the wheel, in relation to the axel, when I pivoted the snout of the pinion up to get the correct angle the 1" longer top link translates to (because of that axis point of the lower link at lower edge of the wheel) the top of the tire/wheel moving backward in the wheel well about 2 1/2". That making the trailling edge of the tire about 1 to 1 1/4" closer to the rear edge of the wheel well. Damn, damn, damn, so next part of the story.

I pulled the wheel, put the top links back together made them 9 1/4" long and reattached them to there mounting points, shock eye center to center still near 15" all set up as it should be as if bolt ed in from the box per instructions. All is good the wheel/tire is back to the center of the wheel well the shock mounting bolts 15" apart and parallel, top and bottom, but......pinion angle is at 80 degrees, pointing in a more downward direction, than a near level or slight upward angle that is the 92 degrees to match the motor and trans. All is great except for that major downward pinion snout angle which can only point to both top and bottom bracket sets are clocked out a certain number of degrees on the axel housing for whatever reason. Which brings me to part three of the story...please bare with me. I have to do this all with in the edit feature to keep it all in the first post since when I write slow I get kicked out and loose what I have typed. In someone replys as I'm writing. Sorry, dont know why it does it.

The lower link bars will have to be able to be shortend up and the upper links will have to be able to be lengthened. this allowing the lower mount to be pulled forward and the upper mount to be pushed rearword in a sence clocking the pinion angle into place without moving the wheel and tire backward in the wheel well which is ugly and not an acceptable appearance, very noticeable. All of this works to acheive the pinion angle but at the expense of then having the upper and lower shock mounting bolts no longer parallel, but I can figure out a way to shim the lower mount at an angle in conjuction with making for a little wiggle room on the top bolt holes. To me this would be a lot easier than redoing the whole thing.

It is the weekend now and I only was able to talk to Frank on his personal time when I got a hold of him. I know he has his well deserved time away from us. I will try to pass on what I found when he is back at work unless he happens to read my scratch here.

Anyone reading this probably would jump to the conclusion that I am tring to get something for free, but beleive me I would be very happy if this was not a problem and I bolted it in and of to the next phase. Ive had the links painted rear smoothed up in heavy powder coat and just tring to move on. It was mock tested for fit but not down to final pinion angle. Just to mention when the pinion is at the 80 degrees if I pull the bottom of the angle finder out about 1/4 to 3/8 of an inch from the lower u-jount mount surface that is what it takes to simulate 92 degrees not much there but it gets multiplied as a problem as you rotate the axel to compensate.

P.S. I will download pics, to help translate or make clearer what I'm trying to say, as soon as the wife gets thru setting up our new laptop we got so I can communicate with the world when I am up in Alaska forever.

[ProdigyCustoms]

No chance this car has a aftermarket full floor in it is there?

[Munster]

No chance this car has a aftermarket full floor in it is there?

Frank

Car was 90k original, no evidence of repair down to factory body work under the orignal first factory paint. Floors still perfect and all stock jute and sound pads and overspray was present.

Quarters and mini tubs were done with very minimal if any fit problems and were only done to get the Camaro look.

[Vegas69]

Sounds like you need a set of adjustable lowers where you can center the axle in the wheel well square to the car with the proper pinion angle. Then you can either move the cradle on the frame or have some longer upper bars made. What is your drivetrain angle? I still wold like to see you level the rockers and measure your actual drive train angle to make sure it's not out of spec.

[Munster]

Im starting to beleive that for whatever reason the brackets got welded on a couple degrees off. Any suggestions on how to measure or compare pics to verify this from anyone would be appreciated.
My wife should be done with the computer swap in a coulpe hours so I can put up my pics. Then someone might be able to care them to some they might have. The big tale tale thing to me is when I look at putting the pinion angle right and it pulls the lower shock mounting bolt way out of parallel with the upper one which is part of the airbar bridge and only can go in one way with almost no room for error. The pics will show how well everything lines up but with pinion pointing down severly.

[Vegas69]

That sure is the only logical explanation unless the lower bars were made to long. Maybe get some specs from Chris Alston on how long they are supposed to be.

[JRouche]

If you are positive with the your pinion angle measurements, and perfect on the ride height it seems like a simple fix is shorter lower links. Pretty easy fix. JR Oh, but that puts the shock mounts off from vertical huh? Hmm. A spacer on the bottom shock mount will fix that.

[Munster]

That sure is the only logical explanation unless the lower bars were made to long. Maybe get some specs from Chris Alston on how long they are supposed to be.

Vegas69

What you mention, I already mentioned to Frank earlier. I was looking at my packaging receipt from air ride tech, to see if there was a miss ship on the link bars and noticed that the part numbers for the links seemed pretty close to there length in inches so I measured them and they are the same length as if there part number was in inches. So I take it they made there length as part of the part #. And they are right.

[Vegas69]

I'd tape the car as well. You can find body specs on camaros.net easily. I'm sure Frank is getting at a floor pan that was welded in to far to the rear. Even if you think it's stock, measure it. You can meassure from the shackle bushing housing to the hole for the finger in the leaf spring shackle housing on the body. There is a spec. If that checks out then it has to be your rear.