Front end aint a bad idea. But didnt all 96 cars have.the bigger balljoints? Not bein an idiot but wouldnt the wider track be a negative to the handling? And also arent the Dbody frame axle mounts farther apart than the Bbody axle? Could you just transplant all rear braking to ur axle or find SS rear? Unless of course u prefer drums.

Also... got a pic of said caddy? Thats like an el camino aint it? Id rock that thing if its driveable... itd be like a 'classy' mullet

 

I believe the FW rear axle mounts are the same as the B body. The rear track should be about the same as a B4U, because the FW has fender skirts, and is limited in axle width. Some people have successfully installed a sedan rear in a wagon, so even if the mounts are a little off, it will still work, unless you are road racing. The wider the track, the better the handling in general. If the rear track is noticeably wider than the front, the car can have a tendency to oversteer in road racing conditions. You should measure the rear, and compare it directly to your original one. Guessing, assuming, or thinking something usually gets you in trouble.


The FW rear may not be equipped for antilock brakes, so check it before installation.


The only B bodies that had the larger BJs were the late police versions.

 

Thanks guys...+1 on the 5/8 ball joints on the 9C1's, but the commercial chassis got them too...it also has a huge front rotor, a good 3/8" thicker than a standard B body. That is the Cadillac J55 brakes, I think. I guess the wider rear track would come from the 3/4" wider rear brakes. I guess I could just pull the drums and brake hardware. It will push the wheel out another 3/4" each side...only concern would be rear wheel bearing loading/center. Guess I could run it until I blow-out a bearing

The rear is a 14-bolt with a 9" ring gear..out to be bullet-proof.

Unfortunately, the entire car is not available...it is at a pick and pull near me. The front clip and lf LCA, spindle, and brake hardware are already gone.

 

I would measure the rear brakes before doing any swapping of the brakes to your original axle. Your axles may not be long enough. If you are going to use the rear brakes swap the whole rear.

 

Just note that the front hubs are huge. I can't fit my wheel caps for any of my wheels properly. Also on the 9.5 inch 14 bolt rear the backing plates are much different than the 8.5 inch 10 bolt so no way to just swap brakes. The rear will fit just fine but will need a new drive shaft as the way it fastens to the rear is different. Also I believe the rear gear is 3.63 or 3.66 in the 14 bolt.

 

You can check the SPID for the gear ratio. 3.73 is GT4.

 

Unfortunately I have no RPO codes as they are normally under the trunk lids in the Fleetwoods. And hearses have no trunk lids. The commercial chassis are called chassis incompletes and are only complete from the front doors forwards. Then the coach builder builds everything from there back as well as the roof with most of it being some kinda fiberglass/plastic type stuff. Some hearses have steel rear end doors. Mine is the fiberglass/plastic stuff. the rear side doors are steel though.

 

Then get out the marker, and put a mark on the top of the wheel/axle, and count the turns of the pinion shaft to make one revolution of the axle. 3.73 is about 3 3/4 turns. 3.66 is 3 an 2/3 turns, etc. You do not have to open it up to find out what gears it has.

 

Won't help the previous owner stuck 4.10's in it with a TruTrac diff.

 

Bumping this old thread up since it's nearly the same as what I'm looking to do...

I have a 1996 Buick Roadmaster Estate Wagon and a 1996 Cadillac Hearse/Commercial Chassis. The hearse is stock, clean and in good working order with right about 100k miles on it. The Roadmaster has a 2012 Duramax/6L90E swapped in. I don't plan to go crazy with the power, but in stock form it has 525 ft-lbf of torque right at cruising RPM's and with tuning it won't go down .

I do plan on pulling trailers and it will see sustained loads, not just quick dragstrip runs. Tire size will be the same all around and probably in the 265/40/22 range so there will be some tread on the ground and weight to hold it there. The Roadmaster is ~500lb heavier than stock (and about 500lb lighter than the stock hearse).

Is it worth it to swap the front spindles/brakes and 9.5" rear end with larger drum brakes between the two cars? Will there be a meaningful improvement in torque handling ability, braking, brake fade (anything else?)?

Anything else I'll need/want to swap or know about swapping the parts? I'm not concerned about the hearse loosing capability, the 8.5" 10 bolt in the Roadmaster is no slouch and won't see a hard life in the hearse, same with the brakes.

Driveshaft is taken care of - the one in the roadmaster was built with this swap in mind so it's just a U-Joint change to swap the 9.5" rear end in using the same driveshaft. Will need to do the same (but opposite) u-joint swap in the hearse.

ABS is not a concern - front only, no rear on the 2012 ABS module.

Another option is to leave the hearse alone and do one of many full disc upgrades in front and disc conversion on the 8.5" 10 bolt in the rear. This looks like it would cost at least $2k (likely more), but will it outperform the commercial chassis in braking? It will look much cooler for sure, but I'd much rather have it perform well than look cool. This option has not addressed the strength of the 8.5", but maybe it's not a weak link?

I'm planning on a full front and rear suspension kit from SpeedTech - Suspension - control arms(all 8), viking double adjustable coil overs, etc so would like to make this decision before I order so if there's anything I need to order different, I can do that. Near as I can tell, it should just swap over. Need to check the flange to flange width of the rear end vs the 8.5" in the Roadmaster, but that's likely just a wheel offset/backspacing adjustment.

Once all this is done, then I can get the wheels/tires sized up after everything is located and finally get this portion of the car done!

What do you guys think? What would you do?

 

F U B, Save the hearse (coach) and you may want to consider this. https://www.spohn.net/shop/1978-199...1978-1996-GM-B-Body/Driveshafts-U-Joints/Moser-Engineering-Ford-9-Rear-End.html
It's just an idea you may not have considered.

Mark: Snowman-33

 

gbhs72 - thanks for the link. I wasn't aware of a "bolt in" Ford 9" option. That bugger is spendy though at $4k with the basic options. Will a Ford 9" be better at sustained loads than the GM 9.5"?

The hearse would not be scrapped - I would put all the Roadmaster parts back on the hearse to keep it functional.

 

I'm not sure if the Ford is stronger but suspect it is. I know the $ is high on that but you're putting a bit of torque on any rear. I think there are some other companies that do the Ford 9.5 conversion. I just wanted to give you a starting point. You may be able to also get the parts to do the conversion yourself as it appears you're set up for quite a bit of fabrication. I'll do some checking to try to help out. I did understand about the Caddy but thought keeping original was a better deal in the long run.

Mark: Snowman-33

 

I re-read your brainstorming and questions above, and admit a tad uncertain of the variables. From what I think I'm reading you're contemplating parts swaps between the diesel RMW and unmolested hearse? I also sounds like concerns regarding trade-off between economies of 'free' parts v. compromised performance or strength of one or both cars?

In any case my potshot from the gallery would be:
Leave both projects as independent (and therefor cleaner) exercises.
Take the learning curve from the wagon and stick another monster motor in the hearse. It sounds amply stout for that already without a buncha' other upgrades.
Build up the wagon's undercarriage to match its new drivetrain if that's the concern. Don't rob from the hearse though.

It's fun helping spend your $$$. I hope I at least got the intent right so we'll be in for a neat build thread.


EDIT: Haha overpost alert! - Mark, as usual evil minds think alike.

 

Cadillac commercial chassis

a Ford 9" is not necessarily stronger than a GM 12 bolt which is a 8.5. The main reason people are hot to trot with the 9" is it is a snap to change gear ratios quickly. Great if your a racer. Normal street use-----not so much. Back in the 60's Buick used the same type differential so its been done by GM

 

a Ford 9" is not necessarily stronger than a GM 12 bolt which is a 8.5. The main reason people are hot to trot with the 9" is it is a snap to change gear ratios quickly. Great if your a racer. Normal street use-----not so much. Back in the 60's Buick used the same type differential so its been done by GM

F U B, I found this that may help you DIY https://www.hotrod.com/articles/120.../articles/1206rc-swapping-a-10-bolt-for-a-9-inch-while-retaining-gm-suspension/ Be sure to check the pictures.
Also you can check with Strange Engineering and Currie.
I do hope all this is helpful.

Mark: Snowman-33

This is very helpful - Thanks for taking the time to share the knowledge and experience you have. That article (and pictures) highlighted a lot of the things that I'm looking to do with the rear suspension. I'm planning on using coil overs in place of the rear shocks with softer springs to dial in the ride height while empty, but then also adding air bags in place of the rear springs and retaining the load leveling system. This way as the load goes up, the air bags will take up the extra load and maintain ride height.

Chevy Man - I'm pretty sure the GM unit in the hearse is a 9.5", not an 8.5" - same/similar as 3/4 ton trucks of the same era, just with the 4 link suspension mounts instead of leaf springs like the trucks had. I agree that changing gear ratios quickly is not an advantage for me. The hearse has 3.08's vs the RMW's 2.93's so no plans to even change gear ratios if I do the swap.

 

F U B, I found this that may help you DIY https://www.hotrod.com/articles/120.../articles/1206rc-swapping-a-10-bolt-for-a-9-inch-while-retaining-gm-suspension/ Be sure to check the pictures.
Also you can check with Strange Engineering and Currie.
I do hope all this is helpful.

Mark: Snowman-33

 

96 Black - thanks for taking the time to review and reply.

My apologies if I didn't come across clearly, but you did a great job of summarizing.

I'm looking at the hearse as "free" upgrade parts for the RMW and I get to keep both vehicles running by doing the swap. It just costs time/effort (and I'm sure some minor little things). I'm not too concerned about compromising the performance/strength of the hearse by putting the RMW parts on it and if I were to sell it that way, there would be full disclosure. After this 5 year RMW project, I don't think I'm up for doing anything major to the hearse - it's just a clean driver.

I'm having a hard time justifying the $ to upgrade the RMW components (brakes and rear end = $6K-$8k) when I have the hearse sitting there. The assumption is that the hearse components are a significant upgrade and are up to the task. If the hearse components are not a significant upgrade and/or would fail anyway, then there's no point in doing the swap and I need to look into other options.

 

Ah So.... Yes appeared a ton 'o work in that motor swap. OK. More outside thinking = if 14-bolts are anything close to what's in a 2500-3500 then sounds satisfactory for your driver. So, find a Beat2S hearse roller and use or rebuild the rear for the wagon. You get those $$$ back and more selling a non-Frankenstein-ed hearse.

 

Bob, you hit my thoughts exactly. And too, the OP has put a lot into his project and it appears to be a long run keeper. This was my reasoning behind the Ford cwm8 recommendation. You express things more eloquently than myself. I prefer to PUNt.

Mark: Snowman-33

Thanks again for the perspective - it's helpful. I'm nearing the end of this project (and need it to be done for my own sanity), but need to balance function, cost and time spent to do it "right".

I was able to find another hearse (1993, clean runs/drives and only like 60k miles on it), but the owner wants more than I'm willing to pay ($2500) and I'd feel bad cannibalizing another good/clean hearse. I was hoping it was junk and he wanted $500 for it .

I'll do some more looking in junkyards and such to see if I can find one where I can get the front brakes and rear end. I agree that it would be easier to do this and not have to reassemble 2 vehicles.

Another option is the "do nothing" approach - just leave all the RMW parts in there and see how long it lasts. Maybe put a temp gauge in the rear end like big trucks have to monitor temperatures? Any trailer over 3000lb will have brakes on it anyway. The risks here would be any "permanent" modifications that I make to the rear end would need to be repeated if I were to change it out in the future (coil over brackets, airbag brackets, etc). One thing I'm also trying to avoid is having to re-buy new wheels, so if the 9.5" rear end is wider/narrower than the 8.5" RMW rear end, that would force the rear end decision to be made before wheels are sized and purchased.

 

Bob, you hit my thoughts exactly. And too, the OP has put a lot into his project and it appears to be a long run keeper. This was my reasoning behind the Ford cwm8 recommendation. You express things more eloquently than myself. I prefer to PUNt.

Mark: Snowman-33

 

So here's a little more reference material for you. Might save you measuring the rear on your RMW. https://www.impalassforum.com/vBulletin/5-drivetrain/237620-rearend-widths.html

Mark: Snowman-33

 

Wow - almost a 4" difference in width between wagon and sedan! I'm surprised it's that much. Interesting that the commercial chassis would have a narrower rear end than the wagons?

I'll have to get the hearse on the hoist again and measure things up to see where everything lays out.

With the lower control arm mounting being ~2" wider than the sedans, that must be why all the rear swaybars say "Don't fit wagons" Anyone know of wagon RSB's available?

Are the lower control arms otherwise the same as the sedan versions? Can I buy impala SS rear control arms and have them fit in the wagon? I have not seen wagon specific controls arms.

The hearse definitely has the 9.5" rear end and 3.08 or 2.93 gears from when I had it up on the hoist and counted turns. I was able to find a junkyard hearse that has the front/rear end available for fair money so that's a viable option at this point.

What is everyone's thoughts on the front brakes? Is the larger caliper, thicker rotor and larger wheel bearing a worthwhile improvement?

 

What is everyone's thoughts on the front brakes? Is the larger caliper, thicker rotor, and larger wheel bearing a worthwhile improvement?

Are you referring to RPO J55 - limo spec front brake package?

If you don't care about ABS, the RPO J55 front brakes alone are an improvement on the 9C1 front brakes [IMO], nevermind the other improvements.
9C1 & J55 calipers have extremely similar mass, so roughly tied there. J55 front rotors are more massive than 9C1 rotors. Use WX3 brake pads with J55 calipers.

I believe the larger J55 wheel bearing necessitates the use of
Fleetwood limousine/commercial knuckles
92-05 RWD Astrafari lower control arms (cheaper than limo LCAs), which come with 5/8" balljoints
limousine / commercial outer tie rods

NavyLifer's HD12 kit is more expensive than a J55 conversion, but in all the time I've spent on the ISSF, I have no memory of a single review of his kit that was less than glowing.

 

Only to get your hopes up, but I have this possibly false memory of a FOMOCO production bar acting as a cxover for the rear on a wagon.


Also, some guys have substituted a Trailblazer design bar for B- and/or D-. It MIGHT be hackable to a wagon.



You sound like a perfect candidate for Navy's HD-12 Big Brake Mod. Cutting hats and special hubs and such, but way bigger rotor mass and scads cheaper than aftermarket racing options.

 

Only to get your hopes up, but I have this possibly false memory of a FOMOCO production bar acting as a cxover for the rear on a wagon.

Your memory is NOT false. https://www.impalassforum.com/vBulletin/21-wagons/231762-wagon-rear-sway-bar-ford-specs-pics.html

 

From the other thread on using crown vic RSB's on wagons...

Not at all to detract from the great info by using the Crown Vic RSB's on the B-body wagons, but there may be another option.

A 96 Cadillac Commercial Chassis has a rear sway bar installed. I need to take some measurements to see if it's a fit for the wagons or not and will update this thread once I have more info and better pictures.

For now, this is the only pic I have, but will get more of how it mounts, and overall dimensions compared to a roadmaster wagon.

It won't fit. It fits sedans, the wagon bar is wider. You can use a sedan bar if you use the Metco LCA's that have holes for both types of anti sway bars. Best bar you will find is the solid 1.5 Herb Adams type bars. But you will need to upgrade the front bar as well. You end up with a very neutral balanced car

If the RSB on the hearse is for a sedan, that would imply the control arm mounting points are sedan dimensions as well - right? Does this mean that the 9.5" 14 bolt rear end in the hearse won't swap into the wagon since the axle mounting points are narrower and the wagon frame mounting points are wider (for the lower control arms)?

Upgrading both front/rear sway bars is in the plan - just need to figure out which rear end will be used...

 

From the other thread on using crown vic RSB's on wagons...





If the RSB on the hearse is for a sedan, that would imply the control arm mounting points are sedan dimensions as well - right? Does this mean that the 9.5" 14 bolt rear end in the hearse won't swap into the wagon since the axle mounting points are narrower and the wagon frame mounting points are wider (for the lower control arms)?

Upgrading both front/rear sway bars is in the plan - just need to figure out which rear end will be used...

The LCA mountings are the same sedan to wagon. But by using a sedan width axle in a wagon then the angles of the LCA will be off and therefore the RSB will not fit.

 

Only because of all the welding you put into your centerlink, it seems it'd be little challenge to reposition the LCA axle mounts from a sedan rear to fit the wagon. If that frees up options a bit.

 

Yes - moving the lower mounts wouldn't be a big deal in the grand scheme of things (though I'd have to do it on both axles). I'm also concerned with the flange to flange width of the two axles along with wheel/tire fitment.

At this point (with a lot of unknowns) going with Navy Lifer's HD12 kit on the front and leaving the 8.5" 10 bolt in the rear is looking like the best option!

I'll know a lot more after next weekend when I can get the hearse on the hoist and take some measurements. I'll be sure to take pictures and provide updates accordingly to share what is learned.

 

I was talking of the extended control arms. I've seen some people have problems with larger diameter tire on sedans. I'm a total idiot on the wagons rearward of the front seat. I'm just trying to wisely spend your money. You know, Fix until broke. (Too soon)

Mark: Snowman-33

 

Got it - thanks for clarifying. I was planning on adjustable upper/lower rear control arms to be able to center everything as well as get pinion angles and such where they need to be.

Fortunately, I haven't spent much more than time at this point, which will hopefully prevent both kinds of "broke" in the future

 

Need the ground clearance due to the lowered front cross member, but don't want it to look "weird" so figured a big rim and big tire would keep the proportions looking normal.

The 255/70/15's are ~29" OD and I'm looking to be in the 31" range.

The 31x10.50-15 is on the front and the 33x12.50-15 is on the rear. The 33 won't fit on the front (else I'd have a picture of that ).

It's close, could probably use a little clearancing if one were to actually drive it.

Front

Rear

Frame Front (more clearance in the rear...)

And right up the skirt

This is kind of what I'm going after for a look, but using the more 80's turbine looking wheel photoshopped below