Saw this on CL in Seattle.

1987 Westwind 27 Ft Motor Home

The one photo from the rear shows the spare and it sure looks like a 5X8" wheel to me. Interesting that it is an '87, so you could swap in front discs and a newer rear without losing the lug pattern.

 

I mostly agree, but there's one aspect yet to be documented.

No question, those wheels are Budd #89340, 19.5" x 6", that use 8R19.5" tires. They work well on F-4/5/6s, F-500s, and some F-600s. But this wheel/tire combo is a shorter diameter (about 34") than stock 7.50 x 20"s (about 37"). The fact of this being listed as a 1987 model is interesting to me. The last catalog reference I have for these wheels is 1979.

The motor home is either a Dodge RM400 or RM500. The rear axle is a Dana 70 that carries their Bill of Materials (BOM) code 603652. The axle ratio is 4.56/1. I had one of these axles myself intending to use it to build an F-4 tow vehicle. But after a while saw it wasn't getting done so sold it to a guy with an F-5 that did the same with it. The axle will mount to the stock springs with about 1/8" difference on each side. I think grinding the ears off the perches on the obstructing sides to allow the clips to pass is the only structural modification needed.

The front disc brakes are the remaining uncertainty. I still have the front hubs and disc brake assemblies from the donor motor home I used. My idea was to adapt them to the stock Ford spindles to avoid having to adapt any of a truck's steering geometry to the motor home's axle. This is where I stopped. I had gathered these pieces, and a 460/C6, but had not made the final jump to finding an F-4. If anybody wants to tackle a disc brake conversation I've got the pieces. Bring a strong back, they're heavy.

There they sit, out of the way under my F-3 MH chassis.


Here's the Dana 70. Stu

 

Stu, how would you mount the calipers to the stock spindles? Wouldn't you need to use the spindles from the motorhome chassis? That brings up my next question, is the stock motorhome front suspension a straight axle? If so, are the kingpins similar in dimension? If not, could the spindle's caliper mounts be welded to the stock Ford spindles?
I am asking all of this because I haven't cracked my F6 brakes apart yet, and if I find that the drums aren't any good...

 

Good questions. I didn't pull the front brakes myself, the yard I work with on the wheels torched an axle at the outsides of either the coil or leaf springs. Don't know which. My idea was to pull the hubs with brakes attached to compare to stock spindles. The other possibility is to see if the king pins are of similar size to make the swap there. But that would mean you have to deal with mods to the trailing arm and pitman which gets you into steering geometry. Stu

 

Looking at the hubs, are the bearings on them similar in size? When I had my motorcycle shop, I would go to a bearing company to buy my bearings, it was far cheaper than going to the Harley-Davidson or Honda dealership and paying their premium prices. One time I went by there with the stock front bearings for my '80 F100 shop truck to get replacements and they told me that Ford wheel bearings are proprietary and they did not have that size available; I would need to buy them from someone who sold the licensed bearing size (the usual auto repair outlets like NAPA or AutoZone). This leads me to wonder if a bearing could be had that has the external dimension of the Mopar bearing (the hub size) and the internal dimension of the Ford bearing (the spindle). If that can be worked out, then the next step would be to fabricate a mount that attaches to the spindle that holds the caliper in the correct position. If the stock caliper mount bolts on at the backing plate location, modifying that to fit may be the way to go (I am speculating but you have the parts there so you could look at them and make that judgement). Correct alignment of the caliper would be the issue to overcome, rather than steering geometry.

 

I'd suggest you grab that motorhome to do the research. I cut bate on the project because of other priorities. I'm not pulling mine apart any time soon. Stu

 

Hey Stu, just wondering where the BOM number would be located. Maybe there is a tag? The local scrapper has a few big truck rears laying around. Maybe he has one I can use on my F4. I assume the 4.56/1 ratio would be a good one with the crashbox. This is an area I'm not too confident with. Also what sort of mod's. would be needed to swap the front axle?

 

The BOM is real prominent, don't recall whether stamped or tagged. I never got myself an F-4 to figure out the installation. Stu

 

Toby, I see two areas of concern for the front axle swap; the steering geometry (which could be overcome by including the Dodge steering pieces and figuring out how to mount them to your frame, including the steering gear but that may be the hard way, I would have to look at all of the pieces to say for sure) and the location of the spring perches on the front axle. I don't think that the overall width is significantly different, but I could be wrong.

Stu, I thought about picking the MH up but towing it 150 miles with an F250 isn't appealing at the moment, weather being what it is (cold with high winds).

 

I've never heard that one before about proprietary bearing size. I've purchased several Ford wheel bearings and other Ford tractor bearings at a good bearing shop.
Something else to consider when adapting an outside spindle is kingpin angle in addition to size.

 

Not a bearing shop, a bearing company. Here is where I used to buy my bearings when I was building motorcycle engines, unless the costumer specified the bearings:

- Bartlett Bearing Company, Inc.

 

I kinda thought that if the rear was an almost bolt on swap, the front might go easy too.Oh well, guess I'll have to get used to the factory setup. I plan on picking up a booster from the truck I got my cab from, will still have drums all around. Thanks for the replies guys.