Mopar B Body PH bar issues

[mrn2obelvedere]

Hello all,

I am trying to install a panhard bar into my 1967 Belvedere and it is fighting me all the way.

I have purchased a diff mount that I really like

http://www.speedwaymotors.com/Behind-Rear-End-Panhard-Bar-Bracket-Clamp-On,7731.html

After a mock installation this weekend I have found that there is no way I will be able to mount this bracket without relocating the shocks. Basically there is some taper on the diff housing as you move away from the center on a Mopar 8.75 rear and there is only one position where the bracket will physically bolt on, and when the suspension compresses the shock comes into contact with the mount.

In the pic below you can see the configuration of the 67 belvedere rear end (this car is off of ebay, but you get the idea...I only wish mine was this clean):

https://static1.pt-content.com/images/pt/2009/11/plymouthrear-1.jpg

One solution that I thought of is that I can mount the right rear shock on the front side of the housing, using a flipped left shock mount. The shock mounts are integrated into the leaf spring/diff mount). Then I would still need to fabricate an upper shock mount.

Any ideas would be very much appreciated.


Thanks!

[John Wright]

Is it the diameter changes of the axle tube that is giving you the problem?...if so can you take the two halves and face them off on a grinder or head surfacer so that it will fit the smaller diameter?

[BMR Tech]

Those are some crazy shock angles. They don't leave much room between them for mounting your PH mount. You always want to make your bar as long as possible so the shock relocation may be your best solution. That way you can position the mount all the way out at the leaf spring to get the longest bar possible. Regardless of the axle tube diameter, I would find a solution that would let you mount the bracket where it needs to be. Mounting it right next to the differential would make the PH so short that you would get excessive axle movement when the suspension compresses or extends. If I remember correctly the 8-3/4" rear axle tubes taper from 3" to 2-3/4". You may be able to do what John recommended above and face the two halves to reduce the ID enough. Other solutions would be shim stock or welding the bracket to the housing (if that is an option).

[mrn2obelvedere]

The 8.75 tapers from an ovate shape at the center to a 3 inch diameter tube at the ends. Its a beefy piece. I would actually have to grind out the panhard mount to move it in closer to the center, which would compromise the integrity of the mount and also shorten the panhard bar, which I obviously don't want to do.

Are there any issues with mounting the right shock on the front side of the differential, basically the same position but on the other side of the axle?

[mrn2obelvedere]

Here's an idea I had today, not sure if its worth investigating.

my car has a couple of tow brackets that I was going to just leave off (easily a few lbs each), but I was thinking about it and they might make good shock mounts. What if I mounted this to set of plates that sandwiched to the trunk floor? See the image below. Do you think this would be strong enough or should I go ahead and weld in an extra cross member for the offset shock? (As for the drawings yes I am a solidworks geek I know)

https://static1.pt-content.com/images/pt/2009/12/shockschematic1-1.png

[JRouche]

First off, I wish I had the skills with SWs that you do. Damm... Next. I know what you are looking at with the taper. My ford nine inch tapers off just like that then to three inch tubes.

I think the longest PH bar you can fit is the best.

I dont see a problem with mounting one of the shocks forward of the housing. Some car come that way right? Now which side to offset? Im sure there is a reason to have one forward other than the other. Would it be for wheel hop? Im not sure. But I would look into which side would benefit you cause you can mount the PH bar to either side of the housing right?

I think you found a solution. Now..... The sandwiching of the floor for the upper mount. Im not sure what your floor looks like. If its got some nice ribs bent into it, like your drawing I think the plating idea will work. And I started thinking if the plates were also channeled to follow the contour of the floor that would be better. Then maybe not. If it was the same shape as the floor it might not be able to take advantage of the stiffness the channel provides. With flat plates sandwiching the channel it might force the floor to take any bending forces (good thing) instead of just increasing the surface area of the floor.

Dunno, might be worth thinking about having the plates mimic the shape of the floor.

Ideally you would put in a cross member. If you have the space.

But anyway, I think you are onto a fix. And with the shock out of the way you can put a long PH bar in there. I would go out as far as you can with the bracket...

Looking forward to seeing what you come up with!! JR

[mrn2obelvedere]

Really I am just not looking forward to the prospect of fabricating a crossmember and having it welded in. I know it will be a real pain to get to and the whole car is covered in undercoating underneath so I will have to get under there and clean that out all around any potential welding areas. It would just all be much easier if I don't have to weld in a crossmember. Space isn't a concern at least not for a crossmember. In my opinion it would be better to just weld in a crossmember between the subframe rails, this would stiffen the chassis a bit and also provide a stiffer mount for the shock, like I said I'm just not looking forward to doing any kind of welding, scraping, cleaning, etc.

Also, that clamp on mount is directional, it needs to be mounted on the right side of the axle, otherwise the PH positioning holes will be elevated rather than lowered.

[LowBuckX]

What about mounting the panhard on the front of the axle. Dont laugh they sell reinforced panhard bars with a arch to clear the nose of the rear end...

Page 76 in this catalog they are called truss style panhard... I considered doing this myself.. http://www.portcityracing.com/general/assets/swf/all-in-one/index.html

[High Plains Mopars]

You can buy prefabbed, OEM style upper shock mounts and just mount one of those in the plane in front of the axle. http://www.autorust.com/shop/product.php?productid=16353&cat=253&page=3
Much easier than fabbing one up. I'd be reluctant to put a shock mount, even sandwiched with plate, into the sheet metal floor. I have seen a car that attempted to do that using chevelle shocks in a mopar, and they eventually punched their way through the floor. the sheetmetal right there is pretty flat and thin.

[mrn2obelvedere]

That is certainly nice...albeit a bit pricey. Probably worth the money though considering how much time , money and effort I'll spend on fabricating a tubular crossmember.

[mrn2obelvedere]

I think I've more or less decided to fab a crossmember for the front mounted shock. Even though I'm lazy, its the laziness that makes me only want to do it once!

[mrn2obelvedere]

test post

[JRouche]

I think I've more or less decided to fab a crossmember for the front mounted shock. Even though I'm lazy, its the laziness that makes me only want to do it once!

hahaha.. You sound like me.. I see it already. Yer looking up at all the area that you gonna have to clean off, what a pain.. But in the end you will know you did it correctly. And after all the work you will be confident knowing it will hold up.

Ive had to do alot of work on the underside of my car after it was already done, in paint and done as far I was concerned. Just to have to wire wheel all the coatings off to prep for more welding. Protecting all the other components in the process. I have had to lay several welding blankets all in and around suspension members just to make sure I didnt hurt them.

The worst is when I had to plasma cut all around components. I layers blankets and metal plates, the plates came in after I completely cooked a welding blanket up due to the heat. I actually had to cut up some custom pieces of 16ga steel just to fit around some members. And yup... I could have disassembled the components to protect them. But the time to make barriers was less than the time to disassemble the components.

I hate working on a finished car. Or in my case a half finished car. JR