Astro van cat conversion

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The other guys disc brake setup.....Mine is a spin on the same idea....
I am excited to have a foot brake that does not use the diffy bands to stop with.

This will save the bands me thinks.......

The new outboard brake brackets are all finished.....(Accept for paint...and that can come after the brackets are welded to the pivot tubes)

Got after this little project this morning and carefully aligned the pieces of the brackets with the calipers aired up to keep everything clamped correctly and then got the assembly outside and welded the parts.

Keeping things from moving while welding can be a challenge.
Tacked things up well and swapped sides with the welding until it was done.

Let things cool and bolted the parts back together.

Yessssssssssssssssssssssssssssss.....about as good as one can expect..

Once the caliper assemblies go onto the cat a new set of pads will be installed to allow setting the brackets such that there is a little bit of slack with the new pad in place and the pistons fully collapsed......

A guess at best...but as long as new pads can slip in...WE'RE GOLDEN.

Glad to have this little project done.......

Still need to fabricate and machine the adapters to bolt the rotors to the Sprockets though.

Gotta check out the sizes of things and and decide exactly what materials will work.

I need to figure out the size bearings needed to pilot the pivot tube into the adapter......

All in good time...

Nicely done. Whats the plans for powering the brakes, manual or power assisted?
Also the photo you have of the "other guys setup" any feedback on how well it works? I can tell ya we do alot of snow wheeling with our trucks up here and when the wheels pack full of snow brakes suck real bad. I realize they are "secondary" brakes but curious as to how well they actually work when packed full of snow trying to stop a huge track on a heavy machine, and the S10 calipers your using are significantly smaller than the other guys dual piston caliper setup which looks like a Ford SD caliper? its 1ton for sure and a dually rear disc. I think its a great idea like you said, save a lot of wear on the bands if it works.

Thanks for the compliments.

Gonna go with a single system mid 60's era GM 1" bore master cylinder on the S10 vacuum booster.
The S10 BLAZER is no 7000# beast, but the cat goes 15 MPH max and the Blazer is gonna be able to do way faster....

From what I heard about the other guys 2100 van cat was that it got away from him coming down a steep grade and he grabbed the steering levers and things got hinky...Damned near tossed it off a cliff.
Serious need of fresh shorts......
The 2100 originally had a foot brake in the hydraulic system to run both bands at the same time for stopping.
I assume that had been removed as has mine.

The hydraulic power controls to the bands are great, but the ON / OFF does not give any really good brake control.

The smaller cats like a Spryte with the hand levers are a different story.

I am gonna go with aggressive pads and that should be enough to provide a reliable way to anchor the beast.

Grab the tranny shifter and roll it down into the gears....then use the brakes if need be.

I did not hear anything bad about the other guys setup....

Yes...I agree..snow may cause some issues.

Back in the day I had a 1976 Ford highboy 4x4 and used to haul the sleds into the hills...I had that thing into deep snow a lot and never really had any issues with it....

Brake pad composition may be the key...I don't know.....

Ceramics are great when dealing with heat.....Metalics are good with high heat...

I have not found an really good data on SNOW AND COLD....

We shall see.
They do make Kevlar pads....they are supposed to be great stuff

The brakes on that other cat had GMC 3500 dually rotors and calipers.

I did the research and am pretty sure on that..
The cost for the calipers and rotors is pretty heady $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
The two calipers, rotors and the new brackets set me back $114 total
Brackets were $36 for the pair and the used S10 rotors and calipers were $78

Snow cats are like boats....they don't coast much.....

Do I know exactly how this will work ??? NO....But we will be the first to find out.
At least the calipers and rotors were meant to work together...

My big worry was having something that will help stop it in the event the engine quits.
I'm running the band steering cylinders off the power steering pump through a pressure regulator set at 400 PSI
This is Thiokol specs for the 2100

Should be interesting

NOT EVEN SNOW CAT RELATED......BUTTTT I discovered this little ditty that is close by here.
Not a prank...But instead the idea of a lumber company higher up and their Forester.
Located to the south of HWY 18 near Willamina Or.
Enjoy

Snowy Rivers said:

Thanks for the compliments.

Gonna go with a single system mid 60's era GM 1" bore master cylinder on the S10 vacuum booster.
The S10 BLAZER is no 7000# beast, but the cat goes 15 MPH max and the Blazer is gonna be able to do way faster....

Click to expand...

You are 100% correct. I tend to forget that cats go slow, coming from a go fast/racing mentality I'm sure the brakes will be adequate. Unless you have the parts already, should take a look at a hydroboost system from a typical 80s chevy diesel pick up might be a bit easier to package without the big vacuum booster. Looking forward to seeing what you come up with!

Yeah buddy
We think about 5-7 K beasts traveling like a bat outta hell and needing to stop in less than a mile and a half.

The slow nature plus the fact that these tracked rigs do not roll easy either......
I have the original brake booster on the S10 cab that it came with. The booster on the rig is fairly compact too.

The hydroboost systems are way cool, but I think that basically tossing the vacuum booster that's there would likely not gain much overall benefit to things.
The Astro vans had a hydrobooster setup that are compact to fit in the cramped nose of the Weeee little vans...
For now all I need to get things going is the single system master cylinder and the lines/hoses to plumb it in with.

The plan is to use small box tubing and frame in the area just ahead of the cowl on the cab....then sheet it with aluminum tread plate.
Then add an ANTEATER nose that tilts forward.
Easy access to things

Step 2:

SWEEEEEEEEEEEEEEEEEEEEET..
That's the cat'sass

I see another Snowy change order coming up.

Well....lets not take it that far .
The little tag along is way cool....but I really don't have a use for a pup trailer.

I THINK (Subjective) that the basics are pretty well coming together now, and as far as any major CHANGE ORDERS go I hope things can continue to move along on the current direction and not need any major changes
The Cab from the S10 and the pickup box are pretty well chiseled in stone now.
This plan makes repairs and access easy......
The hydraulic steering and losing the air system just makes good sense....
As long as we stay with the small block Chevy and the TH350 tranny anything can pretty much work.

The one thing that is still sitting in the wings though is the idea of replacing the little 305 with a small block 400.
The 305 will be fine and get things up and running so the package can be wrung out and bugs worked through.
Do I need a 400....NO but it's an I want.
I had originally gave thought to using a 6.2 Diesel....Just too big...too heavy....
The 6.2 fully dressed is about 700lbs and the small block is about 450lb (The 391 Ford weighed 650)
The weight reduction will save the front axle some extra beating..

I would like to fit whatever SBC that ends up in the package with a large capacity gated oil pan that can handle steep up and down grades without oil starvation.

The 391 Ford that was in the 2100 had a deep sump pan to maintain good oil reserves to the pump
I am removing the big sump in the tub that the pan fit in...Gonna clean up the belly of the beast.
Come summer the power pack will come back out to finish welding the mounts and then clean up the bottom of the tub.

That includes fitting a cover plate over a big hole in the belly under the tranny that was cut by others at some time.
At least the plate came with the cat....
Back in my boat racing day we used a wide pan with gates that allowed oil to flow back to the pump but not the other way.
The gates also prevented tight turns at speed from tossing oil away from the pump.
For now the stock chevy pan will gitterdone.


The venerable mouse motor is so cheap and so easy to get anything to fit.
There is probably an adapter kit to bolt a mouse motor to a mail box....

Just got off the phone with the outfit that water cut the snowflake centers for the new cat wheels.
I made a CHANGE ORDER
The new wheels are a tad smaller in the center than what I had originally expected and the finish is so clean that I am having the center bore on the part opened up to just a few thou over 4 inches.

I will be able to toss the part in the lathe and machine off less than 3/16" and then bring the fit up to where the centers will just tap into the wheel.

This will make life far easier.

I have a 5 on 5-1/2 heavy center coming from the derby shop to become my JIG to locate the lug holes.

Once I get the new sample piece then we can do a bit of machining and things should fall into place and wheels can be made fairly quick.

I ordered 4 more wheels from the depot the other day.....

These heavy center wheels should be rugged as all get out.

I am excited to get this critter a reality and things ready to start making 8 wheels and maybe 10.

If this works out well...If anyone needs wheels for there Thiokol...let me know and I can get the centers cut and you can weld them into wheel blanks.

At $20 each for the 12" wheels almost like Christmas.....

Snowy Rivers said:

Well....lets not take it that far .
The little tag along is way cool....but I really don't have a use for a pup trailer.

I THINK (Subjective) that the basics are pretty well coming together now, and as far as any major CHANGE ORDERS go I hope things can continue to move along on the current direction and not need any major changes
The Cab from the S10 and the pickup box are pretty well chiseled in stone now.
This plan makes repairs and access easy......
The hydraulic steering and losing the air system just makes good sense....
As long as we stay with the small block Chevy and the TH350 tranny anything can pretty much work.

The one thing that is still sitting in the wings though is the idea of replacing the little 305 with a small block 400.
The 305 will be fine and get things up and running so the package can be wrung out and bugs worked through.
Do I need a 400....NO but it's an I want.
I had originally gave thought to using a 6.2 Diesel....Just too big...too heavy....
The 6.2 fully dressed is about 700lbs and the small block is about 450lb (The 391 Ford weighed 650)
The weight reduction will save the front axle some extra beating..

I would like to fit whatever SBC that ends up in the package with a large capacity gated oil pan that can handle steep up and down grades without oil starvation.

The 391 Ford that was in the 2100 had a deep sump pan to maintain good oil reserves to the pump
I am removing the big sump in the tub that the pan fit in...Gonna clean up the belly of the beast.
Come summer the power pack will come back out to finish welding the mounts and then clean up the bottom of the tub.

That includes fitting a cover plate over a big hole in the belly under the tranny that was cut by others at some time.
At least the plate came with the cat....
Back in my boat racing day we used a wide pan with gates that allowed oil to flow back to the pump but not the other way.
The gates also prevented tight turns at speed from tossing oil away from the pump.
For now the stock chevy pan will gitterdone.


The venerable mouse motor is so cheap and so easy to get anything to fit.
There is probably an adapter kit to bolt a mouse motor to a mail box....

Click to expand...

My 2 cents-Honestly I would avoid the 400, they lack center cooling ports between cylinders 3/5 and 4/7 and are prone to over heating. I would go with a newer LS based engine, 6.0/5.3/4.8. They're EFI, lighter, make more power and have a better oiling/pickup system. Same bellhousing bolt pattern, so your TH350 will bolt right up and can be found in the junk yard everywhere for cheap, especially a 5.3 or 4.8.

Yessssss
The 400 will overheat if you work them hard in extreme weather.
I had a 400 in a GMC 3/4 ton 4x4
Never had an issue with heating though.
The thing was a turd though. When it comes to power it is not much when you need stump pulling ooooomph

Actually for this cruising cat I don't think it will really take a lot of power to get it down the trail....especially without the 14 foot blade up front.
Even though I own an aluminum 5.3 in an 07 Avy I am not a fan of the LS.
They can be converted to a Carburetor fueling and a distributor kit is available.
Just really happy with the old school Q jet and a large cap HEI ignition..
The Avy we have is the E85 Flex fuel beast with the AFM (4 CYL shut down)
Just not a real fan of the electronic nightmares.....The old HEI was a very simple system.....

Not to be a total negative on the LS....they are built real well. Y block with cross bolted mains....pretty good little critter....I am just an old Luddite I guess....
I wanted a big block in the cat.....no room.

Another thought about swapping to an LS at this juncture.
Everything is already set up to work with the GEN 1 small block.....Changing now would pretty much be a complete start over.
The exhaust would need to be reworked as well as a lot of other stuff.

I think staying with the Gen 1 family will be a better option as far as $$$$$ outlay.

Got the one new wheel center out and in the lathe this morning.......Cut the OD of the center plate to fit the wheel rim.
This was the first center I had water cut....and I spec'd it a tad too big....BIG TAD TOO BIG

Chewed it down to size so it fits the wheel ring.

Then tossed it in the mill and bored the center out to 4.030"
The next time these will have the center water cut to size and the OD at 9-7/8" so it only needs to be trimmed a little to tap into the wheels.

Well now.
I shot a video yesterday while machining the new wheel center bore.
This morningg it took an update on the YOUTUBE APP and then beating on it to figure out how the "New improved" version works.

We now have it online.
Nothing fancy...just the facts.

The noise you hear after I shut the mill off is the Rotophase running. (3 phase power gizmo to the left on the floor)

Well.....SOME UNEXPECTED GOOD NEWS
Got a text from a local fellow who has some THIOKOL ALLOY WHEELS AND SOME TWO PIECE STEEL WHEELS.

Looks like these may be coming my way soon.
The two piece wheels if I remember correctly were an optional choice on the 2100
My parts book shows the Alloys as listed as a first choice for the fronts, then the steel two piece for axle 2 to 5 with a "standard steel wheel" also available.

If all goes well and this deal falls into place I will likely use the alloys on axle 1 and 5 and then decide on what to do on the center wheels.

There are 4 two pieces wheels and then the new ones I am fabricating.

WE shall see how this comes together.

Possibly I will finish up my new wheels and use them on the axle 2 3 4
This little scenario is making me a happy camper.....

Getting tires and wheels back on the FrankenCat is gonna be a great step in the right direction.
The dented up wheels and ragged tires currently on the old girl are a real sore sight.
I recently picked up a bucket of new lug nuts to replace all the originals.

Some of the old stuff are 3/4" size and some are 13/16" size

Gawd. then I discovered that some clown replaced the studs on one hub with 9/16" studs
Arrrrrrrrgh
I picked up a fresh hub to replace that mess.

There may be studs with 1/2-20 threads and a bigger knurled shank
All new bearings are sitting on the shelf....so things can move ahead on this front.

Any chance the wheels from that burnt 3700 fit the Frankencat?

Sure could
Problem is 1000 plus miles between me and it.

Yeah there is that...

And UPS wants money to drop them off at your door.

The local fella here has some usable stuff and we will likely do some trading on the stuff.

That sort of stuff gets spendy to ship.....I bought 20 track guides from Northern Cal and the came USPS FLAT RATE
2 boxes that were all chewed to rat crap by the time they got here.
I am not much into long road trips now...With Covid it's a pain to get food and lodging.
Sleep in the rig and eat at Mac's Arrrrrrgh

Really a shame to see that 3700 go up in smoke.
All the fires this year have been such a tragic mess.
We had fires around us back in Sept.
That was the worst and closest we have ever had fires close to us here at the ranch

More goodies here.

The 5 x 5-1/2" pattern ring showed up today.
This bad boy will allow me to get a nice accurate set of holes in the new center plates.
The outfit that is cutting the center plates on the water jet called up and the revised piece is ready.

MONDAY.....we will get it and see where we go.

The trade on the wheels deal came through.

Fella brought two alloys and four of the two piece rims over today.....

I sent him home with the Blade and all the stuff I had with it (Cylinders, brackets and mounts) the emergency hydraulic pump, main hydraulic pump and the original drive shaft from the 2100.

Now he is happy, I'm happy and I don't have to mow around the blade stuff sitting in the grass come spring.

With what I have now the plan is looking like the Factory alloys will go on the front and rear axles and then maybe I will build 6 of the "Snowflake" wheels with my centers and use them in the center 3 axles.
The two piece factory rims are nice...just wish I had more of them.
Not enough of any one style...so its gonna be a cat of many different wheels....

Maybe paint them all different colors too......OMG.

No 2 parts alike.

Maybe .....

I am thinking....NEAT, but with a Rat Rod kind of slant to things.

The entire FRANKENCAT idea is sort of like that old Johnny Cash song about his buddies car of many parts that he rolled out of the car plant in his motor home.
Indeed this cat is certainly looking like it.

Maybe I need a couple Tucker parts and maybe some Bombardier stuff too..
So far we have Thiokol, Chevy, Ford and a host of home spun parts.

Ah yessssss
With the addition of all the wheels things are starting to look much better.
One of the jobs now is going to be carving the old tires off the alloy wheels......

That looks like a pain in the butt to me...

Sawzall and a bit of patience.
The alloys are fitted with the smooth Falline tires and they are filled with foam....the tires are literally shredded from time and hard use but were still working..but they need to be replaced......

Function...function...function.........

Needs something from Chrysler and toss in some random metric hardware just to make it fun.

HAAAAAAAAAAAA.
No worries.

As far as metric goes.....I am well equipped with metric tools.

I hated it back in the 80's when GM started introducing metric fasteners on their rigs..../and it was a mixture of both.
They even had some metric threaded fasteners that had SAE heads on them.

Some engines were all metric EXCEPT the bell housing bolt holes were 3/8"-16 (Standard course thread)

A 10 mm would sort of work but was trouble if mixed in.

Stopped off at the Steel shop and picked up the revised "Snowflake" wheel center (The second one to be cut)
The modifications turned out to be quite nice.

These mods are going to make finishing the part a lot easier.....AS IN MUCH LESS MACHINE TIME FINISHING THE PART.

The next step is to go ahead and finish up the jig to drill the lug stud holes and the tool to locate the center plate in the wheel for welding.
The factory wheels on the Thiokol cats (At least the Spryte and the 2100 and possibly the 3700) have a 3/4" negative offset

The wheels actual center is offset towards the outside from the actual point of contact between the wheel and the hub flange.
Nearly all trailer wheels are 0 offset (Right on the C/L)

4 more wheels ordered....should be here soon.

Depending on how I feel about things....at the present I am thinking seriously of using the stock alloy wheel/hub units on the front and rear axles and the new custom ones on the center 3 on each side.

At least this will make things look like maybe some thought was given to the lashup...

We'll see how it all shakes out....

Moving ahead

The second order of 12" wheels showed up....Depot sent me a message and those bad boys are sitting in the shop now.
Not much else happening the past few days.
With the holidays just around the corner time seems to be consumed by so many other things.

Ahhhh.
Almost forgot.
The 60 degree countersink to finish the lug stud holes arrived.

A countersink is not a countersink.

Flat head bolts use an 82 degree tool
Lug nuts are USUALLY 60 degree....but the agricultural hubs use 45 degree nuts
The Thiokol used the 60 degree nuts.
So....the new hubs I have installed on the rig came with 45 degree nuts.

No worries.

If any of you order up the Ag hubs (exact match for the Spryte and 2100) be aware that the lug nuts are 45 degree tapers and are not suitable for use with the Thiokol wheels.