polyurethane cab mounts

[jsteppe]

Hello I have a 1981 k10 that I would like to put new polyurethane cab mounts on. The old rubber ones are crushed and falling apart. The problem is I can't seem to find a set that comes with bolts. Does anyone know what size and thread bolts I need ? I was hoping to get all the parts before I tear into my truck because I want to be able to drive it. I don't want my truck sitting there unusable because I'm waiting on bolts. As soon as I figure out how I will post some pics. Thanks for any help.

[ssxty8]

Are they shown here?

Good luck.

[79Betty]

Problem there is those bushings are rubber. I'd just get some bolts from rural king, as that is what i do. Nice black paint with shiny blue grade 8 bolts! If u give me an hour i can give u dimensions even.

[SkinnyG]

I would like dimensions (cab bushings are next on my list).

[Ziegelsteinfaust]

I got the prothane kit from summit, and it came with a couple of bolts. Most you just reuse.

[jsteppe]

The bolts are shown in LMC if you get the rubber replacements. But I want the poly ones for longevity. I suppose I could order the bolts from LMC but I can probably get them cheaper from somwhere local and I can't find the size listed on LMC.

[Ziegelsteinfaust]

Lowes in my area has a great bolt selection.

If not try Grainger.

[ssxty8]

In that case, just make sure you use grade 8, and if possible, use anti-seize, for the next restorer. LOL

[SkinnyG]

I have a poly mount kit, but before I get in there and shear off all of my existing cab bolts and have to drill holes to free the captive nuts, can someone tell me the lengths of these bolts I should buy? It would be easier to have bolts in hand at the time.

[franken]

I think cab bolts are not captice, but mine are brazed to the cab floor. I have a rubber mount kit, but have no intention of trusting the Asian bolts. I'd replace with grade 5 or 8 from NAPA. My guess is home store bolts are Asian grade 8 which is at best a roll of the dice.

Thinking of the rubber, and remembering a Chinese filler neck grommet that didn't survive a Texas summer, I wouldn't use that either. Sure no sun underneath, but if it can't stand sun, air must be toxic.

I'd use the rubber as patterns to make aluminum pads the same thickness.

As an aside, the original rubber lasted 40+ years.
Chinese rubber lasts less than a year.
In the US we make plastic Coke bottles that will last almost forever.
Someone should be laminating plastic bottle bits and making stuff from them. If you're a tree hugger, plastics are largely made from oil, like a great many things we use daily.
Sorry, rant mode off...

[ssxty8]

Originally Posted by franken

I'd use the rubber as patterns to make aluminum pads the same thickness.

Ditto on the aluminum bushings, have those in my 68 Camaro and I love them. Paired with good components, they let the suspension do their work.

[Tom]

Poly cab bushings make the ride harder then a blown shock on a fully slammed truck. I made the mistake once on my old 79, never again.

[WyattEarp18]

I bought a kit from prothane.com and it requires that you use all original bolts except the two long rears. It supplies the two rears. Only thing about polyurethane is you have to cut the cylindrical mount pieces by about an inch to fit the shorter mounts

[cadillac_al]

jsteppe, what is wrong with your original bolts? heads rusted off? I just put poly bushings on my 76 GMC and the original bolts were fine. They will only be screwed in twice in their entire life. The poly bushings ride a lot better than the worn out rubber ones and they are nice and tight and don't squeak. I don't know what everybody complains about.

[SkinnyG]

The bushings do not "move", so they should not squeak. Control arm bushings often squeak, sway-bar end links never do.

Can anyone tell me how long the bolts are?

[SkinnyG]

I am pretty mad tyte yo at Google searching to find information. I cannot find anywhere on this site or others where anyone mentions the cab bolt size. Frustrating.

However.... Good News!!!!

My cab bolts came out really easily!

I was expecting broken bolts, drilling holes in the floor to access the captive nuts, re-drilling, tapping, and general unpleasantries. This went super easy and slick.


Old and Busted


New Hotness

Here are the bolt lengths - all bolts are 1/2"-13 (UNC):


Showing one side only; you need six bolts total

[WyattEarp18]

Why aren't you using the original bolts? Thats what all the kits call for. If any bolts are supposed to be different then they'll be provided. If you need a size pull one of the bolts for a reference. You're making it a lot harder than it is.

[SkinnyG]

I had asked back in post #4 for the dimensions, so I could buy bolts in advance, in anticipation of them breaking.

Not speaking for the original poster, but my winters up here are harder on fasteners than yours in Nevada. I make it a habit of getting replacement undercarriage fasteners in advance. I had to cut all of my leaf spring bolts just to remove the leafs from the truck (rusted solid to the bushing sleeve).

[WyattEarp18]

I doubt your winters are worse than mine. From September to may we have snow on the ground and almost every year have the coldest temperature in the continental United States at atound -25 and I rarely have issues with boltsbbreaking. Now if you're stupid enough to try and pull bolts on a vehicle thats been outside in 0 degree weather for a day then yeah you can anticipate to Break bolts all day. I work at cortez gold mine and I work on CAT 797s in -10 degree weather but we use oxy acetylene torch with a rosebud tip to heat bolts, pins, etc.. when we can't get them in the truck shop. The cab mount bolts don't see hardly half the weathering that the suspension parts do because the nuts are part of the body and covered by the bushings.

[v30crewcab]

I'm pretty sure he means they use a metric ton of salt where he lives, which equals rusty useless bolts. glad they came out for you. I have had cab bolts not come out down here where I live. stripped out in the cab.

[ssxty8]

Poly bushings should last you for a long time, but the use of anti seize on that kind of applications is always recommended. Most likelly you're going to be the next Guy replacing them in the far future.
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