55.2-59 Who makes quality motor mount rubber? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RyanPartridge · 10-12-2019, 02:49 PM

Found that my rear motor mount rubber/polyurethane is super soft and mushy, and likely the cause of my occasional clutch chatter.

Anyone know where to go for quality replacements?
I'd like to avoid cheap materials...
Much appreciated!

1project2many · 10-12-2019, 04:59 PM

That looks like original material alright. The crossmember mounts may still be available from GM. Medium duty trucks used a similar system into the '80s.

FWIW if your truck is a 4 speed the clutch chatter may be due to oil working out around the transmission input shaft. I have this problem in my truck.

Here are some NOS mounts:
https://www.ebay.com/i/113752439818?...caAtB1EALw_wcB

RyanPartridge · 10-12-2019, 05:08 PM

Quote:

Originally Posted by 1project2many

That looks like original material alright. The crossmember mounts may still be available from GM. Medium duty trucks used a similar system into the '80s.

FWIW if your truck is a 4 speed the clutch chatter may be due to oil working out around the transmission input shaft. I have this problem in my truck.

Yeah it's a 3 speed, I wondered the same thing...
Not sure how old that rubber is, but it's super soft and gummy. My truck was originally a straight 6 from the factory but it got a 283 V8 at some point in its history, not sure how many years back. For all I know the 283 was installed when the truck was only a couple years old and these rubber mounts are the same ones.

1project2many · 10-13-2019, 09:02 AM

I know what you mean about them getting gummy. Natural rubber melts at a fairly low temperature so it's possible there was less vulcanizing done to the mounts. Some of the original rubber parts in my old Plymouth have melted from the heat of sitting in the sun.

The later GM mounts, if you can find them, will last for years. I bought mine in the '90s from GM and they're still good. If your truck uses stock style front mounts there is a single mount on Ebay right now. Mine are aftermarket bought from a company that's no longer in business (Golden State Pickup Parts).

https://www.ebay.com/itm/NOS-55-56-5...ty!03103!US!-1

Aftermarket mounts like Anchor usually have decent rubber but the durometer ratings are different so you feel more engine vibration.
https://www.ebay.com/itm/4-PCS-TRANS...sAAOSwoylcN~dM

mr48chev · 10-13-2019, 02:22 PM

Classic parts sells poly mounts meaning that someone makes them and you can probably find them locally https://www.classicparts.com/Motor-Mounts/products/147/

Thing is that it isn't wise to mix and match rubber and poly and if you go Polly you have to go all poly.

RyanPartridge · 10-13-2019, 11:15 PM

Thanks fellas!
I ordered the polyurethane set from Classic...

GreasyLikeaBurger · 10-16-2019, 10:12 PM

Quote:

Originally Posted by RyanPartridge

Thanks fellas!
I ordered the polyurethane set from Classic...

You could have also stopped in at Classic Industries and got one from them, they are really close to you.

RyanPartridge · 10-16-2019, 10:26 PM

Quote:

Originally Posted by GreasyLikeaBurger

You could have also stopped in at Classic Industries and got one from them, they are really close to you.

I looked into that but they don’t say theirs are polyurethane, which made me think theirs are just rubber. I’ve popped by there a few times for seals and small stuff. I think they mostly carry the same Counterpart Chinese stuff that the Car and Truck Shop sells in Orange. It’s not all bad, I’m just picky about when/what parts I’ll go cheap on.

GreasyLikeaBurger · 10-17-2019, 10:12 PM

Quote:

Originally Posted by RyanPartridge

I looked into that but they don’t say theirs are polyurethane, which made me think theirs are just rubber. I’ve popped by there a few times for seals and small stuff. I think they mostly carry the same Counterpart Chinese stuff that the Car and Truck Shop sells in Orange. It’s not all bad, I’m just picky about when/what parts I’ll go cheap on.

Yeah I hear you on that. I basically go in for sheet metal repair panels and some other OE bits. And I will never go on a Saturday again. Way to busy.

RyanPartridge · 10-18-2019, 08:42 PM

Quote:

Originally Posted by GreasyLikeaBurger

Yeah I hear you on that. I basically go in for sheet metal repair panels and some other OE bits. And I will never go on a Saturday again. Way to busy.

Yep! First time I went it was a Saturday, packed. Took a number and waited 45 min.
Now I go on a Tuesday if I need to.

10-12-2019, 02:49 PM	#1
RyanPartridge Registered User Join Date: Dec 2018 Location: Huntington Beach, CA Posts: 144	Who makes quality motor mount rubber? Found that my rear motor mount rubber/polyurethane is super soft and mushy, and likely the cause of my occasional clutch chatter. Anyone know where to go for quality replacements? I'd like to avoid cheap materials... Much appreciated! Attached Images __________________ My 57 truck project

10-12-2019, 04:59 PM	#2
1project2many Registered User Join Date: Mar 2012 Location: Lakes Region NH Posts: 3,158	Re: Who makes quality motor mount rubber? That looks like original material alright. The crossmember mounts may still be available from GM. Medium duty trucks used a similar system into the '80s. FWIW if your truck is a 4 speed the clutch chatter may be due to oil working out around the transmission input shaft. I have this problem in my truck. Here are some NOS mounts: https://www.ebay.com/i/113752439818?...caAtB1EALw_wcB Last edited by 1project2many; 10-12-2019 at 09:49 PM.

10-13-2019, 09:02 AM	#4
1project2many Registered User Join Date: Mar 2012 Location: Lakes Region NH Posts: 3,158	Re: Who makes quality motor mount rubber? I know what you mean about them getting gummy. Natural rubber melts at a fairly low temperature so it's possible there was less vulcanizing done to the mounts. Some of the original rubber parts in my old Plymouth have melted from the heat of sitting in the sun. The later GM mounts, if you can find them, will last for years. I bought mine in the '90s from GM and they're still good. If your truck uses stock style front mounts there is a single mount on Ebay right now. Mine are aftermarket bought from a company that's no longer in business (Golden State Pickup Parts). https://www.ebay.com/itm/NOS-55-56-5...ty!03103!US!-1 Aftermarket mounts like Anchor usually have decent rubber but the durometer ratings are different so you feel more engine vibration. https://www.ebay.com/itm/4-PCS-TRANS...sAAOSwoylcN~dM

10-13-2019, 02:22 PM	#5
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,281	Re: Who makes quality motor mount rubber? Classic parts sells poly mounts meaning that someone makes them and you can probably find them locally https://www.classicparts.com/Motor-Mounts/products/147/ Thing is that it isn't wise to mix and match rubber and poly and if you go Polly you have to go all poly. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

10-13-2019, 11:15 PM	#6
RyanPartridge Registered User Join Date: Dec 2018 Location: Huntington Beach, CA Posts: 144	Re: Who makes quality motor mount rubber? Thanks fellas! I ordered the polyurethane set from Classic... __________________ My 57 truck project



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