72 Brave Front Axle Swap/Disc Conversion

[Bonebag]

Hi everyone. I just picked up a complete front axle from a 73 M300 for my disc conversion. Nothing wrong with the drums on my rig but I'm doing it out of madness so just to get that out in the open. My late 72 M300 has no sway bar and the new axle does. Is there any benefit to just swapping the new axle in and having that sway bar? Are there any other differences in that axle config that might catch me down the road? thanks much.

[Oz]

I can't answer your questions, but nice score on the front end!

[eXodus]

Don't know about other differences - but swaybar vs no swaybar makes a huge difference while driving in Wind and cornering.

I've swapped a larger swaybar in my 1996 Brave - because the factory one was small.  Handling difference was amazing.

[73WinnieB]

As others have said, you'll want to keep the sway bar, I see it as an upgrade. If you have a line on another front end, I'd be interested! I'm in the process of swapping a later model front end in mine and there's lots of differences I'm having to account for.
As to the 73 axle, it should be a direct swap. You should likely check or replace all bushings and kingpins while you're in there.

[Bonebag]

I'm finding out and posted a question in new thread, that the springs are different sizes, the spring hangers are different sizes and not in the same locations, the frame is actually different and it keeps getting better but I'm not deterred

[Oz]

Good to hear you aren't deterred.   Get it done, man!

[73WinnieB]

Well, I apologize for steering you wrong,  I just repeated what I've read here!!
I've also read here... you can swap from the king pins out or the backing plates out on the 73 axle. Backing plates requires tapping one hole... supposedly!
I don't know what year my donor axle is but looks to be the same as the axle in our recently acquired 77 chieftain.
My plan is to redrill the axle locating holes and fabricate a spacer to sit vertically next to the spring pack to keep the leaves from fanning out and use new 3" ubolts.

[Bonebag]

Oh man don't worry about "steering" me wrong LOL...Nowhere does it say everything is the same and my ADD and amazing talent for jumping in before reading the fine print is well documented. The stocker springs will do. I nabbed a brand new firestone air bag set up from the 80s for the front end for under a hundred bucks, in the box,  no instructions. The firestone people found the instructions for me and sent me a PDF as they were unavailable for many years. They wanted me to send them a photo, they were shocked I was interested in the old motorhomes yet. There is a custom spring manufacturer that can make new springs if I need them. A trusted shop that works on trucks from the largest down to 4WD's around here suggested i NOT put new spring hangers on the front seeing the frame is changed from 72-73. The risk wasn't worth the benefit.

[Oz]

No worries.  It's common when dealing with vintage RVs.  Often, it's a  process of sifting through info and actually discovering what works and what doesn't.   

[73WinnieB]

I just completed this swap in my 73 Brave yesterday.
I have 3 disc brake axles here with different casting numbers on the axle beams and associated parts but they all interchange with the 77 Chieftain front axle. So it looks like 73 to 77 8 lug axles interchange. As noted above (late?) 73 up use 3" wide leaf springs whereas 72 down use 2.5" wide leaf springs. To swap a later disc brake axle into my drum front 73 I had to:
press steel plugs into the existing disc front axle perches and re-drill the center pin holes as the later ones were 3/8" too narrow. I also drilled new center pin holes in the sway bar axle mounting bracket. I replaced the spring pack center bolts and added the later model lower shock mounts to the top of the spring pack. Upper shock mount and sway bar bracket will work fine but are located differently than the older shock only bracket so new holes are needed in the frame for the bolt holes.
I am using disc brakes front and rear, swapped to hydroboost and will change out the proportioning valve before my project is done but the valve should be swapped to a disc/drum one if only changing the fronts.

[Oz]

Awesome!  That's a swap that can be used over a wide span of years!

[Bonebag]

Ok...I think I found some of the same issues as above so far. I'm almost done just waiting for some parts to come in like the power booster rebuild. Not available anywhere. I also took the shock mount from the 73 axle and mounted it on my springs with a little modification to make it narrower. The springs on the 73 are wider than the 72. The distance between the springs on the 73 is narrower than the 72. The U bolt holes on the 73 are wider as well, which makes the axle beam itself completely different than the late 72 I have. I am in the process of grafting the shock mounts from the 73 onto the 72 and installing the Ride-Rite Air springs. They too are slightly different and holes need to be drilled out as the 72 has a different frame section up front (completely different) than the 73. But it's coming together

[Bonebag]

Getting there...slowly but surely. Also working on every other aspect of the beast to get her goin'! Working up the new brake lines/and all that stuff. Thanks to Dave for lining me up with the people over at Master Power Brakes that supplied me with a new Brake Combination Valve as the old one from the 73 disk brake donor was pitted pretty badly. Part Number PL3360K. Brake hoses have been kind of a snafu with ordering and receiving different hoses that are either too short or too long or have pins on them that don't line up with the calipers. I'll post the part numbers as soon as I get it together and have a fit for sure. Another snag was the grease zerk on the front axles interfere with the new disk hubs. On the 73 the zerks were on the rearward side of the axles. No biggie, I'll put some plugs in them after greasing.

[Oz]

Nice work!

[LJ-TJ]

  Man oh, man oh man. Your killing it. What a great job. Not to mention I love the way you blocked it up to work on it. I've always been skid-dish about using jack stands. When they brake they got no place to go but down. Well done Mate. well done.

[73WinnieB]

I bought new calipers and hoses. I used Dorman H26913 for the front caliper hose. Try that if you haven't.

[Bonebag]

Ok thanks. I think the hoses I have currently will work. The one you linked shows to be one for a twin caliper that comes straight out of the caliper. I AM HAVING AN ISSUE with the caliper that is listed for the right side (passenger) side, not working but only working on the left (also has an L stamped on the caliper body). If I look at Rock auto, napa or any other place online, they all show the left side caliper with the hose banjo bolt angling down toward the axle body. When installing the part number caliper on the listed side, the banjo bolt and hose contact the axle body limiting the travel of the steering by at least an inch and would easily knock the caliper off the vehicle in use. When using the listed caliper on the opposite side (i.e. Putting the driver side caliper on the passenger side) it works fine. Anyone else who have replaced calipers or done the swap see this issue?