Topic: Marlin Crawler Formula Toyota Buildup

[Marketing]

Our Formula Toyota project is oficially under way. Our DOM chassis from www.hendrixmotorsports.com is on order. The buildup will be based on a Feburary of 1985 EFI short bed pickup previously owned by Shawn Hoskins. The truck was rolled a couple of times and then purchased as scrap by Marlin. Every project starts somewhere, so here is the first photo:



We have cleared a spot in front of our building and moved the truck into position. Yesterday the cab and bed were removed.

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The rules state 4.10 gears must be used. We just happen to have a couple of factory new R&P gear sets that were removed from electric locked diffs sitting on the shelf. We will be using one set up front with an ARB Locker. The rear diff will be a V6 unit with a Detroit locker.

The interesting thing about these electric style gears is they use a larger 30 spline shaft and flange.  Normal 8" gears use a smaller 27 spline shaft and flange. This is not a major failure point but is an interesting difference. FYI if you use these electric gears in a non electric housing, make sure to use the matching electric style flange!

Here is a close up of the spline...

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I just found out that our chassie is number 028.

Today I attacked the frame with the hot wrench and sliced off most of the unneeded body mounts.

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Rocky built up our diffs, front ARB high pinion, rear V6 with Detroit.



Now it's onto the housings!

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It's time to shave the housings:

For those that have not seen this trick before, you can cut off the bottom of the housings and plate it to increase ground clearance. We are going to do a step by step description to show some of the tricks to getting this done without leaks.

The first step is to cut out the bottom sction with a plasma cutter or torch. You must leave the ring around the housing that has the bolts in it.



Using a grinder, we clean up the cutting and doing the final shaping of the hole.

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Note the thre arrows in the photo below, these are the three places most likily to leak. Andy welded up each of these points to ensure we had no leaks later on.



Before plating, we install a junk 3rd member. We don't use a good third member because of all the metal particles from welding and grinding can damage the gears and lockers.

The two bottom studs (top in photo) are removed and replaced with bolts. These bolts will later serve as drain plugs.

The 3rd member is bolted in place. This helps prevent bending and warpage of the housing during welding and fitting.



Using a vise and a hammer 2.5" X 1/4" plate steel is bent to fit the angle shown. Then it is placed on the diff and marked for cutting.

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A small piece of 3/16" steel (see arrow) is used as a spacer between the ring gear and the new plate material. This spacer ensures the new plate is as close as possible but still have enough room for oiling.



With the spacer in place the section is tack welded into place.



The other sections are cut from 1/4" plate and fitted into place using a grinder.

After the pieces are fitted into place, a grinder is used to bevel the edges. This makes for a nice weld when your done.

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Finish welding...



For ring gear protection we installed one of our Differential Armor Rock Plates. For this application we trimed a little off the bottom before installing it.



Once the housing has cooled down, the 3rd member and 3/16" spacer are removed.

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Now for the inside. It's important to weld up teh inside too. This will help reduce the chance of a leak. Install the two bolts to protect the threads.



Spray the inside with anti-spatter. This keeps the welding balls from attaching to the steel and later falling off and into the gear oil.



Weld up each of the seams from the inside.

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We gained 1/2" of ground clearance at the back of the diff and nearly 1" under the front of the diff.

The rear diff will be rotated up so that the drive shaft points directly at the transfer case. On the rear we will see a full inch of increased ground clearance across the bottom.

After welding, the inside is wire wheeled clean. The tubes are wiped down, end to end using rags over the end of a length of tube. Then the housing is rinsed and dried. The idea is to remove any and all steel shavings and grit.

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While Andy is working on the front axle couple of other details will be adressed.

The steering stops on these axles are a little under sized for offroad use. Plating them top and bottom only takes a few minutes and allows them to hold up better. We will be running a steering assist ram and we don't want the ram pushing the stops out of the way.


 


Another clean up item is plating the spring perches. These perches can bend with steady off road use. Using 1/4 plate steel, small caps were made for the end of the perches. These covers are welded into place.

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Here are some shots of the rear housing being shaved and plated. Andy used the same process as the front housing.

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We removed the spring perches on the rear axle for two reasons. One we want to rotate the rear axle up and two we want to inboard the rear springs for better articulation.



After cutting the perches off with a torch, a grinder is used to clean off the last remnants of the perches.



Later, after the springs are mounted, new perches will be added.

[moutaintoys]

  to the family

[greengo]

chris, how much clearance did you gain? do you possibly have a before and after pic, or a side by side. looks good, keep it, and keep the pics coming.

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chris, how much clearance did you gain? do you possibly have a before and after pic, or a side by side. looks good, keep it, and keep the pics coming.

That would make a nice photo. I think I can shoot that.

We gained 1" in the rear and 1/2" up front.

[UNBREAKABLE]

MORE PICS!

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Today, I pulled out the drive train. Removed the steering box, driveshafts and brake lines. Spent a few more hours cutting and cleaning the frame.

[rockbuggy37]

nice job!!
 I think ill add this to my project ass well, thanks for the tips if you have any input on my d44 hubs please reply!

[rockbuggy37]

as well.
sorry!

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Before installing the front springs we are going to replace the hangers. To prevent the frame from bending during the cutting and welding, I added a piece of scrap steel between the frame rails. This will later be cut out and removed.


The stock front spring mounts are weak and after repeated bashing on the rocks can and do fail. Also the corner welds where the front crossmember and frame rails come togther can be a weak spot causing frame brakage. 


After bracing the frame (above), the stock front crossmember is cut out with a torch.


A front hanger assembly is fitted into place. With this hanger in place the spring mounting holes are now 1" higher and 1/2" forward of the factory mounts.


Later the finish welding will be done and gussets added to tie in the front hanger to the frame rails.



Front 3" lift springs and 2" over stock shackles are installed.

[Willy Mammoth]

Chris, what lift are those springs? I ordered your 3" lift springs. I hope they arn't that tall or I may need to do an axle over to get the right hight.

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These are the 3" springs with 2" over stock shackles.

[rockhound]

Cool way to profile Marlin's products. Really like watching the progress. Do you get paid to do this? Where can I get a job like that?
I thought the new spring hanger welded to the bottom of the frame rails, no?

[BigMike]

Chris, what lift are those springs? I ordered your 3" lift springs. I hope they arn't that tall or I may need to do an axle over to get the right hight.

Willy, remember he's using really long shackles and also those springs are unsprung. They will settle down a bit...and since your truck's so light, you might even be able to remove a leaf or two.

I thought the new spring hanger welded to the bottom of the frame rails, no?

If placed beneath the stock front crossmember, then you will gain about an inch of lift.
If placed in line with the frame rails, then you will drop about an inch. Since this will be a buggy, body clearance is not a concern so we can keep the center of gravity down as much as possible and use the 39s to get the ground clearance we lost

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Turning back to the front axle, Rocky added on one of our "no hole" front upper gussets to prevent bending of the housing. This should help keep the axle straight when jumping sand dunes at Pismo Beach!

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Rocky bench tested the front ARB before putting it into the front housing, and tested it again after it was installed. He found that the ARB leaked air when installed. The unit was removed and taken back to the bench and retested. Again it tested fine on the bench.

Going back to the housings, he found that a small part of the fab work done to clearance the housing was touching the side of the ARB locker. This was putting light pressure on the seal housing and causing it to leak. A few seconds with a grinder were all that was needed to allow a gap between the seal and the axle housing.



To prepare for the axle assembly, the inside of the brake dust shields were both cut out with a plasma cutter. The dust shields can trap rocks and generally just get in the way. The center 1" of the shield can be remove and used during the assembly to keep the parts spaced correctly. The outer sections will be discarded.

[4RnrRick]

Keep up the good work. I like the very detailed build up posts like this! really shows the progression and all the little work that is required.

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Heavy duty Bellfield axles and Polly Performance 4340 axle shafts are assembled with new factory c-clips and installed into the housing.

We started with a straight housing and were careful not to over heat the axle with our welding work. We were happy to see both axles slip right into place with no noticeable housing deflection from the 10+ hours of housing surgery.



Small gussets were added to the lower balls. None of us here at the shop have had one of these balls fail, but others have. It's easy to add on so we put them on just for good measure.

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Front axle final assembly was completed, Vented Land Cruiser rotors and rebuilt IFS calipers were installed. Knuckles shimmed and steering arms installed.





The assembled axle received a set of 2" wide front wheel spacers. The size of the spacers may change depending on how close the tires are to the springs. The assembled axle was rolled into position and a front flip kit installed. Upon installing the front flip we encountered a clearance issue with the upper gusset and one of the U bolts. In order to use the gusset with a flip kit, the far right end of the gusset needs to be slightly trimmed.