Renewing NOS cab bushings-- is that possible?

[Mullaney]

Someone brought up last time we went down this rabbit hole that they used hockey pucks and just drilled the center hole on a drill press ! All my body bushings are good but i bought a bag of them for 5 bucks at the flea market the other day and it seems doable to me!

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The ONLY reason that I was hell bent on having the real bushings when I did my replacement was my age. I figured I would do the job once at 62 and whomever has the truck when I am gone gets to deal with it the second time around.

 

[chucky]

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The ONLY reason that I was hell bent on having the real bushings when I did my replacement was my age. I figured I would do the job once at 62 and whomever has the truck when I am gone gets to deal with it the second time around.

HELLS BELLS we will ware out 2 or 3 more sets before before we pull the faders back to black ! Im not even over my collage girl fetish yet !!

 

[Awesomeness]

I think you mean 80. My research landed at shore 80 for the cab bushing (I don't think Awesomeness mentioned a specific hardness in this thread). We've had this discussion in several threads here. Hokey pucks are 90 so there are very close to what is used in most HD bushings.

Agreed. I'm not knocking those who use hockey pucks, but back in the 80's-90's when we had an off-road center here in S TX, we did a LOT of lifts. I've seen body lifts done using hockey pucks that didn't hold up to the elements well (in fact, the mechanics there used to rage on people who had "red-necked" their body lifts with pucks). Not saying that they aren't a viable solution, just saying that I'm not going to use them for the long run.

I suspect that you could even raise the cab a wee bit (help clear 53's?) with the right bushings (limitations being the usual body lift items like hoses, lines, wires, steering).

Correct, the OEM are Shore 80A. Most "performance" bushings are harder (e.g. 90A), both to further limit movement but also to get increased mechanical properties (e.g. tensile strength).

Back in the day.... ( I must be getting old). I had a Jeep with a body lift made from machined aluminum pucks..... I wonder if something like that would be a (better?) option for us? Just replace the worn out rubber with aluminum. How much flex does it really need?

Solid bushings are not advisable. The rubber bushings provide tolerance and movement between the major assemblies of the cab and frame, especially as it twists and bounces. If you switch to solid spacers, the frame still needs to move, so where does that happen? It will likely end up sliding around on the solid bushings, or stretching the bolts, etc.

 

[Mullaney]

Correct, the OEM are Shore 80A. Most "performance" bushings are harder (e.g. 90A), both to further limit movement but also to get increased mechanical properties (e.g. tensile strength).




Solid bushings are not advisable. The rubber bushings provide tolerance and movement between the major assemblies of the cab and frame, especially as it twists and bounces. If you switch to solid spacers, the frame still needs to move, so where does that happen? It will likely end up sliding around on the solid bushings, or stretching the bolts, etc.

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My guess was that bolting the cab to the frame (edit: with solid blocks of aluminum in place of bushings) would twist doors , possibly pop out glass (hopefully not since they are in rubber casing - but still possible) and other things of similar nature (fuse board, etc).

Still would definitely like to see any other comments.

 

[coachgeo]

.....

Hockey pucks will probably dry out and crack sooner than polyurethane would, but it's better than nothing if yours are totally gone. and easier to find and replace when they go.

as to drying out.... coat them with polyurethane first as a protectant. Or any UV protectant you can find. Many construction adhesives are polyurethane. maybe even flex seal (though dont know if chemical structure is Poly or not. )

 

[Awesomeness]

It's not just the UV, though that does accelerate things. (In their installed location, I doubt they are taking much beating from UV.) Elastic materials don't like to be held long term in a compressed or elongated state. Think about rubber bands that you have left stretched around something for a year or two, and they become brittle, cracked, and fall apart. Natural rubbers are particularly susceptible to this, and softer materials with lower tensile strength even more so.

 

[GeneralDisorder]

I reached out with some emails and phone calls to both BAE and a distributor for Hutchinson Aerospace to see about purchasing the correct cab mounts.

The military pays $12.02 for the big ones, and $10.47 for the skinny ones..... $78 for all of them on my A1R.......

We shall see what they say. Might be possible to do a group buy on them since this is one part that we pretty much all need.

 

[Mullaney]

I reached out with some emails and phone calls to both BAE and a distributor for Hutchinson Aerospace to see about purchasing the correct cab mounts.

The military pays $12.02 for the big ones, and $10.47 for the skinny ones..... $78 for all of them on my A1R.......

We shall see what they say. Might be possible to do a group buy on them since this is one part that we pretty much all need.

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I don't currently need any, but if you are able to do a Group Buy, I will happily pay $80 for a full set.
Actually, I would take four complete sets if you can work that deal (plus some freight of course).

If you can get that deal, I paid 4 times that amount for a set - not including the shipping.
AND that was the lesser price when I was shopping...

 

[GeneralDisorder]

Well the word from the Hutchinson distributors I talked to is that these part numbers are marked "no bid" and can't be ordered by any distributor because the tooling is owned by whoever had them design the mounts - which is probably Stewart and Stevenson - now BAE Tactical Vehicle Systems. I sent a contact request to them so we shall see what they say.

Here's all the part numbers I have:

Big mount:

NSN: 5342-01-371-7973
BAE: 12417600
Hutchinson Aerospace, Barry Controls: 25926

Skinny Mount:

NSN: 5342-01-371-7258
BAE: 12417622
Hutchinson Aerospace, Barry Controls: 25920-1

 

[Godspeed131]

I don’t need them yet, but I’d be in too for a group buy if it comes back around as possible.

 

[GeneralDisorder]

Spoke with a gentleman from a rubber manufacturing company - he can make them once he has drawings or samples.

The gist of the conversation is that it's probably going to be somewhere in the neighborhood of $2,000 to create the tooling. And then some minimum order quantity of 100 to 200 pieces which is somewhere around ~30 trucks worth of mounts (A0 and A1 need 6, while A1R need 7) - each mount likely being in the $10 range. That works out to something like ~$4,000 order with each truck costing about $135 for a full set of mounts.

This is all back of the napkin estimating. Also haven't decided on a material but something that's similar shore hardness to stock but doesn't have an 8 year shelf life might be nice.

I think if we put out the word we can probably easily come up with 30 trucks worth of orders and make this happen. Heck I'm down for probably 3 sets myself just for future truck purchases and I'm guessing many members here will want more than one for similar plans. $135 for all the mounts is not bad - heck the military pays $80 for a set but they buy thousands and that's probably a negotiated price from a long time ago with the tooling already paid for.

Also future orders would be MUCH cheaper once the tooling is paid for on the initial batch.

 

[Awesomeness]

Spoke with a gentleman from a rubber manufacturing company - he can make them once he has drawings or samples.

The gist of the conversation is that it's probably going to be somewhere in the neighborhood of $2,000 to create the tooling. And then some minimum order quantity of 100 to 200 pieces which is somewhere around ~30 trucks worth of mounts (A0 and A1 need 6, while A1R need 7) - each mount likely being in the $10 range. That works out to something like ~$4,000 order with each truck costing about $135 for a full set of mounts.

This is all back of the napkin estimating. Also haven't decided on a material but something that's similar shore hardness to stock but doesn't have an 8 year shelf life might be nice.

I think if we put out the word we can probably easily come up with 30 trucks worth of orders and make this happen. Heck I'm down for probably 3 sets myself just for future truck purchases and I'm guessing many members here will want more than one for similar plans. $135 for all the mounts is not bad - heck the military pays $80 for a set but they buy thousands and that's probably a negotiated price from a long time ago with the tooling already paid for.

Also future orders would be MUCH cheaper once the tooling is paid for on the initial batch.

I explained all this in a previous post, and came up with similar, but higher, ROM numbers. Now you're seeing why my bushings are priced the way they are, even without make much/"any" profit on them. Though I think your numbers are overly optimistic. There's really no way to cheat/shortcut this problem.

A couple things to question...
1.) Is your "$135 for a full set of mounts" based on $2000 creating molds for one bushing (e.g. top), or all (e.g. top and bottom)? By him asking you to buy 100-200 bushings, I suspect he's talking about making enough molds/cavities to cast several bushings at once (e.g. "several molds"). With labor and materials factored in, $2000 seems like an amount I would typically quote for maybe 2-4 cavities of a 2-piece mold to make one part. Good platinum-cure silicone molds only last a few dozen parts (~50?), if you are taking really good care of them and using good ("expensive") mold release - cheaper tin-cure molds, cheap/no release agent, and a more agressive casting schedule will shorten the life (12-20?).

2.) Another factor is that the flexible urethane rubbers take a long time to set (e.g. 48 hours). So you either need a bunch of molds, or it's going to take you months to make 100.

3.) The top cab bushing is ~11 floz, and the bottom is ~8 floz. The materials (e.g. rubber + dye + UV inhibitor + etc.) are around $0.75-1.00/floz these days (in container sizes reasonable to make this quantity), making "$10 range" unlikely, when you factor in labor and fees (e.g. shipping/pickup of materials) and consumables (e.g. gloves, mixing cups, stir sticks, shipping box, etc.). Material prices have gone way up the past couple years.

4.) There are no better materials (in this price range order-of-magnitude) with significantly different shelf lives. UV-stabilized polyurethane is about the best you can do.

5.) The military's numbers should not be used for any kind of comparison judgement. They most likely bought a $100,000 injection mold and make them in a completely different kind of way. They run on a $2M automated press, and create one part every 30 seconds. Their pricing model just isn't apples-to-apples... you want 100, which is how many they throw away just to do a test run on that press to make sure it's working.

 

[GeneralDisorder]

Well I assume he knows basically what he's talking about - again this is not a small operation this is a major rubber parts manufacturer and at one point did manufacture one of the two pieces (the smaller one) - and he made no mention of the tooling wearing out for such "small" production runs and said it would be no problem to turn out batches of 100-200 subsequent to the tooling being paid for. And his quote over the phone was actually "$5 per piece" (mind you without seeing them but I gave him rough dimensions) - I doubled the number he gave me figuring it was probably optimistic.

He estimated about a 6 week lead time. It would not surprise me these guys have the injection mold machine that you mention - likely they have a lot of them. They use big hydraulic presses to vulcanize the rubber under pressure I know that much - I assume that must involve it being injected as well...... The difficulty is that I know little about these processes and can only reiterate what I was told. The company has been around since 1930 and as I mentioned at one point they did manufacture the smaller mount as I found a part number from them listed in Fed Log from a long time ago.

Near as I can tell the military mounts (which I have in-hand in their original packaging) with a production (cure) date of 3Q21 are made by Barry Controls for BAE and carry a BAE Tactical Vehicle Systems part number. I have made several attempts to contact BAE TVS and they don't respond to anything - their phone number goes to a "voicemail box that has not been setup" and hangs up on you. Apparently the "tooling" whatever that constitutes is owned by BAE and thus parts made on it are exclusive to them and Barry contractually cannot sell them to anyone else.

I highly doubt BAE gives a crap at this point because the soft cabs have been phased and the A1P2 being built by Oshkosh doesn't use those old style cab mounts for it's 4500 lb cab anyway.

 

[Awesomeness]

Well I assume he knows basically what he's talking about - again this is not a small operation this is a major rubber parts manufacturer and at one point did manufacture one of the two pieces (the smaller one) - and he made no mention of the tooling wearing out for such "small" production runs and said it would be no problem to turn out batches of 100-200 subsequent to the tooling being paid for. And his quote over the phone was actually "$5 per piece" (mind you without seeing them but I gave him rough dimensions) - I doubled the number he gave me figuring it was probably optimistic.

He estimated about a 6 week lead time. It would not surprise me these guys have the injection mold machine that you mention - likely they have a lot of them. They use big hydraulic presses to vulcanize the rubber under pressure I know that much - I assume that must involve it being injected as well...... The difficulty is that I know little about these processes and can only reiterate what I was told. The company has been around since 1930 and as I mentioned at one point they did manufacture the smaller mount as I found a part number from them listed in Fed Log from a long time ago.

Near as I can tell the military mounts (which I have in-hand in their original packaging) with a production (cure) date of 3Q21 are made by Barry Controls for BAE and carry a BAE Tactical Vehicle Systems part number. I have made several attempts to contact BAE TVS and they don't respond to anything - their phone number goes to a "voicemail box that has not been setup" and hangs up on you. Apparently the "tooling" whatever that constitutes is owned by BAE and thus parts made on it are exclusive to them and Barry contractually cannot sell them to anyone else.

I highly doubt BAE gives a crap at this point because the soft cabs have been phased and the A1P2 being built by Oshkosh doesn't use those old style cab mounts for it's 4500 lb cab anyway.

Something just doesn't add up. If they are running it on an automated machine, you're going to pay tens of thousands of dollars for a machined metal mold, but then part cost goes down to material cost basically (because there is so little labor to work the press, besides a few hours @ $100/hr shop rate to set up and tear down the press). If they are making them with manual (silicone) molds, your molds only cost a couple thousand, but the cost per part goes up because of the labor involved in each casting (e.g. mixing materials, pouring, cleaning up, pulling out the castings, getting ready for the next batch, etc.)... it's like an hour of labor per part.

 

[GeneralDisorder]

They make their own tooling in-house and can work from drawing or sample. And I assume this probably greatly reduces cost. These guys have been doing this and specializing in molded rubber parts for over 90 years. My guess is they have it figured out and can pass on the savings.

These really are not complicated parts requiring high precision manufacturing. I would guess that an accuracy of 0.020" would be plenty accurate enough..... I'm sure that this is easily within the capabilities of even 1930's era vulcanizing presses and they almost certainly have newer equipment than that...... If you have a good old school lathe operator that can weld I'm sure a press mold could be whipped up in an afternoon especially for older low volume production machines. I'm just guessing here but the ingenuity of pre-CNC equipment operators cannot be understated.

 

[Third From Texas]

On a side note, my rear bushings failed today on the A1R. I do a visual inspection every time the cab is up, but I was driving down the road today and I heard a sort of "clunk". When I got home, I looked around the cab and can see the bushings are pretty much gone (a few chunks of random rubber remain). Going to go thru the entire truck and inspect the rest of the rubber.

I've not gotten in the stuff to make mine yet, but I do have some hokey pucks I may slap in the back until I'm sorted. Not really a fan of the idea at all, but it will get the truck back on the road asap. Don't want to drive it with no rear bushing (I think Alex said his truck shorted something out when his rear bushings failed on his A1R).

 

[Awesomeness]

They make their own tooling in-house and can work from drawing or sample. And I assume this probably greatly reduces cost. These guys have been doing this and specializing in molded rubber parts for over 90 years. My guess is they have it figured out and can pass on the savings.

These really are not complicated parts requiring high precision manufacturing. I would guess that an accuracy of 0.020" would be plenty accurate enough..... I'm sure that this is easily within the capabilities of even 1930's era vulcanizing presses and they almost certainly have newer equipment than that...... If you have a good old school lathe operator that can weld I'm sure a press mold could be whipped up in an afternoon especially for older low volume production machines. I'm just guessing here but the ingenuity of pre-CNC equipment operators cannot be understated.

I'll believe it when I see it. Engineering this kind of stuff and having it made is what I do for a living (everything from prototype / low volume, to mass production), and I have an entire machine shop of my own in the garage. Most/many shops make their own tooling, so that's not really anything different or cost-saving. These aren't complicated parts, but the mold still has to be fairly high precision to fit together correctly, and have a quality surface finish to have parts eject cleanly.

Something about those numbers you gave is just suspiciously low. I'm hoping he really can make them that cheap, or even that he can't but will sell them that cheap at a loss. But I'm not holding my breath, and would be suspicious even at 2-4x the price you gave.

 

[B-Dog]

Talk is cheap. Only one way to put this to rest

Sign me up for a set. Sounds like 4 down, 26 to go. Thanks for managing this group-buy!

 

[GeneralDisorder]

On a side note, my rear bushings failed today on the A1R. I do a visual inspection every time the cab is up, but I was driving down the road today and I heard a sort of "clunk". When I got home, I looked around the cab and can see the bushings are pretty much gone (a few chunks of random rubber remain). Going to go thru the entire truck and inspect the rest of the rubber.

I've not gotten in the stuff to make mine yet, but I do have some hokey pucks I may slap in the back until I'm sorted. Not really a fan of the idea at all, but it will get the truck back on the road asap. Don't want to drive it with no rear bushing (I think Alex said his truck shorted something out when his rear bushings failed on his A1R).

Mine were also "gone" - especially the rear cab mount which just swiveled around. Previous owner swapped in a single of the thick mount but nothing else. I swapped in all the correct pieces - there's quite a few on the A1R cab latch mount. Two of the slim mounts, one of the thicker mounts, nut/bolt and a sleeve.... and a nylon beveled ring that mates up with a matching beveled piece that allows some amount of movement to let it align to the latch. Also several BIG thick washers. It's quite the assembly on the A1R since it doesn't have the cab air ride.

I was under the impression that Alex's truck shorted out due to some accident damage but might be related to the cab mounts also. At any rate they are a problem even for 2008 trucks so everything older has to be in the same situation if they haven't been replaced.

 

[GeneralDisorder]

Well - here's the deal. I'm going to have 100 of each piece made. The cost is going to be $30 each for the larger mounts, and $24 each for the thinner mounts. This includes the tooling cost, etc. Estimate is about 6 weeks lead time. I'll start a new post for anyone that wants some.