Oldsmobile "Commercial Chassis"

I understand there really wasn't one so to speak. However, my 1970 Cotner-Bevington "Cotington 48," is based on the "Oldsmobile Ninety-Eight/C/B Super Chassis" From what I can tell, they modified it in-house. They specifically mention springs and shock absorbers, front disk brakes, rear brakes, and brake booster are "special." I've got a parts car now to work with for hood, fender, quarter panels, etc. - but mechanically I know there are likely differences. Further, over the course of this ambulance's 30 year career - it's quite possible something got switched out.

1. Are the wheels ambulance/hearse specific? They are on Cadillac as discussed at http://www.professionalcarsociety.org/forums/showthread.php?t=5329 . There were a bunch of old wheels/tires sitting with the car when I got it - as mentioned it was in the midst of a so-called "rebuild" when the previous to previous owner sold it. I wonder if any are the correct ones and some got swapped out. Got 'em all, but just something to think about.

2. How about master cylinder and brake booster? As discussed at http://www.professionalcarsociety.org/forums/showthread.php?t=13123 and specifically in the table listed at the bottom of the page - they were "special" on Cadillac with a 1" bore vs 1 1/8 for regular cars. I'll probably want to rebuild the original anyway - but want to be sure that one itself didn't get swapped out for the "wrong" one during its lifespan. It only shows a single model for Olds 98 on that same chart - but C/B ambulances were more uncommon than Cadillac. Are folks still using Apple Hydraulics? It seems they'll only do the master cylinder - any recommendation for the booster?

3. Are the wheel cylinders and front calipers different? NAPA lists Commercial Chassis specific parts for the Cadillac of same year.

4. Anything else I should be looking out for?

Thanks!

when you get under the car you will notice that CB did not just cut and splice the car. they removed the rails from the GM frame, built, there own to length, re built the wheel arch and added a crossmember. most all the parts on the car are standard 98 parts. but some were swapped out from other GM sources. as for the wheels all the raised roof cars used the heavy duty 3 riveted wheel same as the caddy's. I'm guessing the only sheet metal that will be the same on the car will be the front end assembly. measure out that quarter panel well before you start cutting. CB built there own doors. the only part of that olds door that is the same is the first foot of the inside door frame and the hinges off the front door. I would not beat on the hardware. the plungers at least on the door handles have been modified to work the latches in the ambulance. as you have the two of them handy you can compare casting numbers on things like the brake master cylinder and disk brakes. that will let you know if they are different or CB just went to a Heavy duty pad and called it there own. the 70 would have had the 890 x15s on it so the fender skirts on the ambulance would be modified to fit those tires. the stock skirts will fit with the 235s thought. but once fixed you will have a vary nice car. I love those 48's. still a high top when it comes to washing it but as long as your doing it I'm happy to look. .

Thanks Ed! Very good to know about the skirts and door latches. It makes sense.

We'll check it out. I'm just concerned something might have been swapped out in the past - at least 4 previous owners between Junction City FD, Miltonvale Ambulance Service, Chattanooga Ambulance Service, then two private owners I know of. Thus, while something may be "original" to the car as I got it - it might not be the "right" item or even unsafe! The size (and weight) difference between the coupe parked next to that ambulance is indeed impressive.

There appears to be nothing wrong with the doors on our car. It was the rear bumper, quarter panels, right fender, and hood that need to be replaced. I priced out just those body panels from junkyards and the cost was around $4000, not counting shipping. I can tell you I paid less than that - delivered - for my parts car. And I can sell whatever's left afterwards...

Awesome and useful information. Thank you both!

Awesome and useful information. Thank you both! I had no idea the C/B's roof where steel. I assumed they were fiberglass.

First thing to do is to verify that the master cylinder that you have is original to the car. There is a good chance that it has been replaced along the way. The way to tell if it is original, is to look for the Delco symbol on the bottom of the cylinder. The Delco symbol is a upper half circle and a lower half circle with a small space separating the two halves. If you have that, then it is a Delco cylinder. Next is to look for any casting numbers, and / or any stamped numbers on the flange, or at the front, where the brake line attaches. With casting numbers, I can cross reference it to a part number(s). Oldsmobile used 1", 1 1/16", and 1 1/8" bores in the cylinders in that era. Where it also gets interesting is that they used both Moraine and Bendix units. The rear brake shoes are 11 x 2 1/2", same as the Cadillac Commercial Chassis, and they should be riveted shoes, however, I will need to check to see if they are the same brake shoe number. The one thing that will help to sort all this out, is the rear wheel cylinders, since they are a constant. The choice of sizes is 15/16" or 1". The 1" was used with the Oldsmobile commercial chassis according to my reference material. Are the front brakes drum or disc brakes?

Brakes

I have used this Co= Karps. They can do it all , boosters,master cyl,wheel cylinders .. They can reline shoes and also arc them to the drum. They bond the shoe lining , you will have to call if you want a riveted lining .I think they only do bonded shoes.

When I did the brakes on the below 72 I had as Paul mentioned the only parts I found that where different where the rear shoes that where the same as Cadillac.

I've never been able to understand how Cadillac supplied a pre-made commercial chassis, which was designed and engineered to receive a professional car body. Yet C+B Oldsmobiles (plus Flxible Buicks and Superior Pontiacs) had to literally rebuild and build up passenger car sedan chassis, plus bodies with full professional car glass, yet still sell significantly cheaper than Big 7 Cadillacs. How could they do this? And WHY can't current professional car builders for crying out loud start building professional cars with pro car windshields to eliminate that HORRENDOUS door wedge look they all have now? All modern professional cars look absolutely hideous!

Amen to that. I've always been a big S&S and Superior fan but Accubuilt has really disappointed me the last couple of years. At the National Funeral Director's Convention, they blamed it on Cadillac not giving them much to work with, and I somewhat agree. However, some of the smaller players are putting out a descent looking hearse. I do put a good bit of the blame on the Cadillac XTS design. Hopefully, they will do better with the LTS but I'm not holding my breath. I'm surprised that some major coach builder hasn't totally gone to building their own hearse and forgetting the "big 3" auto manufacturers altogether. I guess that one company did with that Yukon XL design but not sure if they are still doing that. I don't think they ended up being that popular. Just my opinions and nothing more.

they all grew up playing with matchbox cars. the thats what a car should look like generation is up in the work force now and it is showing.

but as for the C/Bs in the Wayne years I have found that the heavy duty 98 olds parts are the norm. with vary few exceptions. the older they get the less the exceptions. if they could modify a olds part to work they did. we have almost every part up here for a 72. here is just a example of what they did on the 72 skirts yours might be different. the skirts were split in the front over lapped and welded. then the dog leg was leaded up. so c/b skirts rusted out fast. they also don't have the front lower stone guard. the lip molding is also longer. as you work on the car you can see a number of places were rather then buy again they would change standard things to meet there needs. in this case it was so the 890 tire would not jam up agents the front edge of the skirt if the suspension in the rear extended. even with the 235s if you jack the car up with the stock skirts on the tire will pinch the front of the skirt.

Abe Bush said:

WHY can't current professional car builders for crying out loud start building professional cars with pro car windshields to eliminate that HORRENDOUS door wedge look they all have now? All modern professional cars look absolutely hideous!

Click to expand...

The reason why has been said many times, but here goes again. Cadillac will not allow the coachbuilders to modify the A pillars due to the structure and air bags in the pillars. When Cadillac says you cannot change them, you have to make do with what you have.

I actually had not heard that before - but it makes perfect sense.

Thanks for pointing that out Ed - I would've probably been tempted to try to utilize the fender skirts off of the parts car if you hadn't of said that.

Paul Steinberg has been awesome, as always, and provided learned guidance on some of the brake components. It appears riveted Commercial Chassis shoes for the drum brakes on the rear are still available. Remanufactured brake boosters and master cylinders are also available for the 1970 Oldsmobile Ninety-Eight at a low cost. However, I'm just paranoid there's something specific about the original ones. I just can't imagine a M-M ambulance of the same year would have a special booster/master cylinder and a C/B would be sent out on the road with the same one a sedan would. The weight difference is indeed substantial, and like has been said here before - if it wasn't important, they probably wouldn't have done it. We'll find out on Monday what's on there and get some photos posted.

Folks - I'm sure it's a fascinating topic to discuss the modern plight of professional car construction - but coming from somebody who's done A LOT of searching through this board, let's please keep this thread on track for the next guy. Thanks.

Daniel Scully said:

I have used this Co= Karps. They can do it all , boosters,master cyl,wheel cylinders .. They can reline shoes and also arc them to the drum. They bond the shoe lining , you will have to call if you want a riveted lining. I think they only do bonded shoes.

When I did the brakes on the below 72 I had as Paul mentioned the only parts I found that where different where the rear shoes that where the same as Cadillac.

Click to expand...

The do riveted linings also, and the cost is about $80 per axle. I got this information from them this past spring when looking for linings for my 1969 Miller Meteor Cadillac.

Nicholas Studer said:

Thanks for pointing that out Ed - I would've probably been tempted to try to utilize the fender skirts off of the parts car if you hadn't of said that.

Paul Steinberg has been awesome, as always, and provided learned guidance on some of the brake components. It appears riveted Commercial Chassis shoes for the drum brakes on the rear are still available. Remanufactured brake boosters and master cylinders are also available for the 1970 Oldsmobile Ninety-Eight at a low cost. However, I'm just paranoid there's something specific about the original ones. I just can't imagine a M-M ambulance of the same year would have a special booster/master cylinder and a C/B would be sent out on the road with the same one a sedan would. The weight difference is indeed substantial, and like has been said here before - if it wasn't important, they probably wouldn't have done it. We'll find out on Monday what's on there and get some photos posted.

Folks - I'm sure it's a fascinating topic to discuss the modern plight of professional car construction - but coming from somebody who's done A LOT of searching through this board, let's please keep this thread on track for the next guy. Thanks.

Click to expand...

General Motors at that time was developing a commercial chassis specifically for the Cadillac line, and as such, it started out with a lot of heavy duty components, since they knew that these vehicles would be substantially heavier than the standard Cadillac. In the early 1960's for some strange reason, GM used different sized wheel cylinders for the Miller Meteor built vehicles, as noted in the parts books of that era. I can only assume that Miller Meteor specifically requested this change, and GM accommodated them in this request. Then, by the late 1960's, that change had been dropped, and all commercial chassis cars used the same wheel cylinder, regardless of the body builder. GM was very accommodating of the body manufacturers.
The Oldsmobile chassis show no designation as to being a commercial chassis specific build, until you get to 1971, where the parts books do show some changes to brake components. This isn't to say that when you take the system apart, and examine the specific part, that you might find that it isn't the same as the Oldsmobile 98 standard issue part. In the late 1960's early 1970's, GM was selling a lot of Buicks and Oldsmobiles to the state highway patrols for freeway patrol vehicles. I am certain that these cars, like the other GM lines that had specific police packages, had many changes that were not made public knowledge to the aftermarket parts companies.
I remember Bill Marcy telling me that he needed a rear axle seal for the 1964 Oldsmobile Amblewagon that he owned, and they kept getting the wrong part, since they assumed that the differential was made an Oldsmobile part. It turned out to be a Buick differential, because the Buick unit was better suited for the purpose that the vehicle was going to be converted for, by GM's engineering department, I assume.