Project BMP

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Things are getting really close now, this week I concentrated on getting the steering ram mounted.  The goal was to somehow spread the load between the upper steering arm and lower tie rod mount on the knuckles.  This is a potential weak point on the D60 axles due to the knuckle casting being thinner up towards the kingpin.  Hi-steer arms also provide a lot more leverage for the forces acting on the top of the knuckle. The solution is to run a bolt between the upper and lower arm mounting it so it is in double shear.

The first step was to drill out one set of the holes in the steering arms for a 3/4" bolt.  Since the hole are tapered, the top portion is already bigger than 3/4".  I didn't like the engagement with the bolt so I made a 1/2" thick plate with a 3/4" hole in it, positioned it over the hole in the steering arm I had just drilled out, and then welded the plate to the steering arm.  The plate also covers up some of the unused holes reinforcing the steering arm.

Since the upper steering arm holes didn't line up with the lower tie rod mount I had to fabricate a small plate which was welded to the tie rod mount, then I welded a tab (with another 3/4" hole) off of that plate to allow the bolt to drop down from the upper steering arm into this tab.

Next, the steering ram was positioned and spacers were made to position the rod ends so the steering linkages were parallel to the ram.  A 3/4 x 7.00" grade 8 bolt was used to bolt the whole assembly together.  I make this part sound easy, in reality it took me 3 tries to get the spacers correct, my mistake was not bolting down the steering ram when I was measuring for the spacers.  The ram was sitting at a slight angle which induced a small error that was magnified by the time you got out to the end of the rod end .

I also added a brace on each side of the axle to reinforce the cylinder mount platform from up/down forces.

The completed steering setup.  The true test will come when I try to take the front differential cover off, we'll see if I left enough room :)  I also had some longer hydro hose made, I plan on running them up the upper link this time to keep them away from the engine pulleys.

On Friday I started in on the rear bump stops.  I need these to be mounted outboard like the front bump stops so they would control upward travel when the axle is articulated.  Since I lowered the chassis in relation to the axles to compensate for the larger tires I have several spots where potential interferences could occur.  Out back the potential interferences are between the rear driveshaft & chassis and upper links & chassis.  To fabricate the bump stop mount I started with a small piece of tube that I put a 90 degree bend in.  The hardest part was getting this tube tacked on so it was straight up and down in relation to the front and side of the chassis, then matching the one on the other side.  It took a few tries but with my wife's help were able to hold the two levels, welding torch, tube and get it all tacked on in the correct spot. Next I gut a gusset to brace it side to side.

Then another gusset braces the mount front to back.  next, I made a small plate to weld to the bottom of the tube that would serve as the mounting flange for the bump stops. Lastly, I drilled and tapped some 1/4-20 holes in the top of the bump stop mounting plate to attach it to the plate.  You can also see where I started to fabricate the bump stop target on the rear axle.

Update 6-19-05 -  The front axel is all done.  Ran brake lines, hydraulic lines and hooked up the front driveshaft.  I had a minor issue when trying to attach the pinion flange, I couldn't find a socket that would fit inside of the High Angle flange.  I tried a variety of 34mm and 1 5/16 sockets but they were all just a hair too big.  Jack had a socket that fit inside the counter bore on the flange, the difference was that his 34mm socket was a 1/2" drive, all the ones I was finding on the store shelves were 3/4" drive. The next hurdle was a dead battery, I couldn't get the engine started to finish bleeding the steering or brakes so I moved on to other projects.

Here's the oil pan skid plate I started to make.  The oil pan is pretty high up in the chassis but I did manage to get a rock up in there the first time out. I have been putting off this project for quite a while.   The goal is to make a skid that will take some hits without ending up with an overbuilt skid plate. Instead of a massive piece of .25" thick steel I am using some 11 ga. steel, the sides are bent at a 50 degree angle for rigidity and I will have some braces along the top for more strength.  The skid plate attaches via some unused tapped holes in the transmission, engine block and to the front cross member. 

I also finished up the rear axle, the last remaining items were rear brake lines, limit strap mount, swaybar mounts and the bump stop targets.  I plan on trying the rig with and without the swaybar to see if the suspension geometry changes will allow me to run without it.  The chassis feels much stiffer when you try to rock it back and forth without the swaybar connected so I have a felling I will have much less body roll.

Update 7-12-05 - Finished up some new body panels and finally added some color to the buggy. 

The side panels are now approx. .125" thick.  I wanted something more robust this time since it take a  lot of time and effort to make a body panel.  The thin aluminum and plastic I experimented with before this did not hold up well in the rocks (my driving may have played a small part in their hasty destruction.) The rear panels are all .050 aluminum, I don't expect them to see much if any grinding against the rocks.  For paint this time I decided to try some of the Rustoleum Hammered spray paint.  I originally looked for the bright red shown on their website but could not find any here in Phoenix or on the net.  It is almost as if that color isn't out yet. The "hammered" in the paint name comes from the texture the paint has when it dries.  I like the texture because it breaks  up the large body panels and hides painting imperfections.  If you have every tried to paint a large, flat panel with normal spray paint you know how hard it is to get a smooth finish (I never accomplished that).

Here's some close-ups of the mounting tabs for the side panels.  I welded a 1" long 5/16-18 coupling nut to the panel, then welded a tab with a clearance hole to the chassis.  I ended up with about 8 mounting points per side panel.

Update - 7-20-05 - Finally have some rims for my tires.  I had originally ordered some Stazworks double beadlocks back in late May figuring 6 weeks was plenty of time to make some rims (was quoted 4-6 weeks). My credit card was charged the day I ordered so I figured this vendor was on the ball,  About two weeks after I ordered the rims I noticed a few posts on one of the bulletin boards where other buyers had been waiting months for their rims. I decided to check the status of my rims weekly after week 3, by week 5 I was told my rims hadn't been started yet and the vendor was making a road tip to deliver rims to another customer which would kill the rest of that week and push the start of my rims out to week 6, the time they were supposed to be delivered. At that point I was pretty much determined to not be the guy waiting months for his rims.  I canceled the Stazworks beadlocks and ordered some aluminum Trailready beadlocks.  3 weeks later the custom Trailready rims arrived on schedule except for one missing locking ring which is supposed to be here today.

After going thru this whole ordeal I was struck by the question "When did it become exceptional customer service to deliver stuff on time as promised?"  When I posted my experience with this vendor on one of the bulletin boards there were a lot of guys trying to defend the vendors actions because they received on the shelf products in a prompt fashion.  In my opinion this is not above and beyond but rather what is expected.

After canceling the Stazworks beadlocks which were made from steel, I decided to go with an aluminum beadlock to save some weight.  The only option I could find for an aluminum beadlock with a 3" backspacing was the 2 piece rims manufactured by Trailready.  Unfortunately they are also the most expensive rims they sell.  In the end I think the cost is worth it due to the weight savings, The Aluminum Trailready rim weighed in at 26lbs with another 5 lbs in hardware and the aluminum locking ring.  The 17 x 9 Stazworks rims I bought used with the Toyota hole pattern a while back tipped the scales at 70lbs ea.   

The first thing I did before assembling my beadlocks was to run a bead of silicone over joint between the two rim pieces  (front and back) which needed to be sealed.  I couldn't see a weld here like my previous MRW rims but it still needed to be airtight.  I also did this on my previous beadlocks and never had any leaks.  I know all rim manufacturers aim for airtight welds but none of them test their welds to my knowledge so it's better to do this step now than find out after the tire is all mounted. 

 

Here's the buggy with 3 tires & rims mounted.  It is finally looking the way I intended it to.  I also weighed this tire and rim combo, 17 x 9 Aluminum Trailready Beadlock + one 42 x 14 x 17 bias ply Irok = 129 lbs.  This is very light for a tire/rim combo in that size.  For reference my 3 year old  37" Baja Claws on a steel MRW 15 x 9" beadlock weighed in at 102lbs.  I also checked the tire height, at 20 psi they were a hair over 40" tall.  My goal was a 39" tire at trail pressure so I think I hit the target.

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