Very cool.  Have you taken it for a spin, yet?  Curious how well it works.  When you get safely back to TN are you going to increase boost?

Nicely done. That should haul enough mash over the mountains and back to the still to pay for the trip.

Seems to me you’re going over a high pass. Highest I’ve had the motorhome was 9300+ at red mountain mt. Would have been nice to have the turbo up there. Enjoy the trip.

Very cool.  Have you taken it for a spin, yet?  Curious how well it works.  When you get safely back to TN are you going to increase boost?

"I thought the core support needed some extra braces from the firewall, I'll have to find those for her truck."

Listen, I think I gave you the wrong idea on the upper radiator hose design. It is meant to allow the upper hose to flex with engine torque. It was the OEM design.

Your present upper hose looks stressed to me and may fail on the road.

Howdy,

No.

I am referring to what appears to be a split-system vacuum master cylinder. 

All these medium duty trucks had single system brakes, meaning that a leak anywhere in the system (front or back)  would result in complete loss of brakes.

It wasn't until somewhere in the 60's (67 or 68 maybe?)  they went to a split system like all cars and trucks are nowadays.

The medium duty trucks used a manual split master with 2 separate vacuum boosters where the earlier trucks (including my 55) had a single manual master with an inline vacuum booster.  They worked ok ....but if one wheel cylinder started leaking enough to put the pedal on the floor, there was no brakes at ! 

I for one, do not like the idea of driving a 7000lb (empty) truck around that could lose brakes due to 1 leak.

So I am using a split master from a circa 2000+ Ford Super Duty truck that has 1.5" pistons. (I think my original had a 1.25" piston)  It requires a hydraulic pressure source so I am using a PS pump.

I suppose I could have just used a firewall-mounted vacuum master but I wanted to keep the master cyl under under the floor in it's original position and use the original pedal instead of hanging a pedal in the cab.

Here's what mine looks like: (that's a 272-Y there with a Bentsen transmission adapter and a Ford E4OD out of a 94 F450 diesel)



The only "downside" is that I need a hydraulic pressure source instead of a vacuum source.....hence the PS pump....... And I'll probably need a hole in the floor to get to the reservoir unless I relocate it.

SO I would love to know how it's being done in the 58F600  I'm assuming that I will need to do something with brake pressure proportioning!

Thanks for that info!

I think I will probably have some "over" assist as you say but I think a hydraulic regulator might temper that.  I was worried about having enough fluid volume with any of the master cylinders that had small pistons to actuate the front and back.

The front brakes on my 55 have single cylinder,  SINGLE-Piston actuators.  Only the top of the front shoe is actually  "pushed" forward. (sort of like a boat trailer drum brake system)

The bottom of the front  shoes are hinged together so they all contact the drum when the top of the front shoe is pushed. 

I suspect they changed that in the mid fifties I just don't know when. Are your front wheel cylinders single-piston too?

I think I couldn't find replacement shoes either but a local Brake place in Tacoma (Cascade Friction Materials) was able to reline both front and back shoes nicely and they also turned my drums.

I am very lucky,   none of the drums had ever been turned and all they had to do is take off a few thousandths to clean them up.  The guy told me I would probably never have to find drums for it.  (I don't think they exist anyway!!)

By then, I'll either be unable to drive at all or I'll put a DANA 80 on the back and a much more modern front axle on it with disc all the way around!

I think you said you're using a T98 transmission with a 2-speed axle.  (5.83/8.11?)

Mine is a 6.80:1  axle  but I also have an Eaton 1350  5.83/8.11 too.  I am not sure I'll be using it with the E4OD. 

The E4OD has a 0.71:1 over-drive ratio.  With the 9.00-20's I have on the truck, (roughly 40"  rolling radius)  I figured I would see around 504 rear wheel RPM @ 60MPH.  504 x 6.8 would then be 3428 RPM in direct drive.

With the 0.71 OD in the E4OD (& torque convertor locked) the 60mph RPM should be around 2400 RPM  (2434) maybe that's about right for my 272?

What size tires do you have and what RPM do you see @60 MPH with the 5.83 rear axle?


Using the 5.83 axle, I calculated with 40" tires I would see 2938RPM  in 3rd gear (TC locked) and 2086 in OD. 

That might be too "tall" in the gearing  for my 272 except maybe on a level highway,  empty with a tailwind!!

The 8.25-20 tires are of smaller diameter but Les Schwab told me they couldn't get them anymore.  My only choice was the 9.00-20's

Now if I were to go to 22.5's or 19.5's I suppose it would be better but when I got my current set of 20" 5--lug lock-ring wheels no one was offering 19.5 or 22.5 wheels.

I think you have more choices in 6-lug wheels.

It was several years ago I got those tires!

The fronts are TOYO 9.00-20 tube-type radials  And the backs are recapped radials.

I would have gotten the 8.25-20's if I could have.

Yeah, I think the 5.83 will be pretty tall with the OD.  I still have to get the axle spindles redone.  one side is damaged from a spun bearing.

I would still like to try it though.  I got the 2-speed rear axle from a guy in Seattle for $100.  The entire pumpkin was a rusty mess and pretty much unusable.  I had a local truck parts outfit find me an excellent condition 2-speed pumpkin for $750 so I bought it.

And I swapped out the vacuum shift unit for the  electric-motor  shift and was able to find all the parts to rebuild it.

Drivelines Northwest did all the drive line shortening etc.

That transmission in my picture came out of a 94 F450 diesel Superduty. 

I knew a guy that worked at a transmission shop in Tacoma and he found a complete transhousing/bell for a 300 I-6.  Bentsen makes an adapter for that bell housing (300-6 and SB Ford V-8) so I could adapt from the Y-block to the trans. 

The transmission internals (and ratios)  are from the Diesel E4OD.  The trans guy also found the tail-shaft mounted Parking brake too.  Those things are very hard to find and usually cost a fortune.  The entire thing was about $1500 for the case swap, parking brake and complete trans rebuild.

I also have a Baumann Engr trans control unit but I may go to the MSD trans control box since it integrates well with the MSD Atomic EFI

I expect that 272 to run well with the MSD TBI system. 
I don't even want to think about how much I have tied up in this thing ....but it's all therapy, right?