C2 Idler Arm

[Rob M.]

I have what I believe is a used original idler arm from a '68. The casting number is GM 3779185 and the frame mounting part is the correct configuration for a Corvette. There is much discussion in the archives on the casting number and configuration. My question is relative to any markings on the frame mounting part of the idler arm assembly. This one has "135" stamped between the 2 bolt holes and the frame bracket is cad plated (the cast portion is natural and rusty). Does this sound like the correct configuration? Would it be correct for 65?

Thanks,
Rob

[Donald T.]

Re: C2 Idler Arm

Rob,

Sounds like the real deal. This would be correct for a non-power steering car. Also make sure it does not have grease fittings. Should look like the pic below of an NOS C2 idler arm.

[Rob M.]

Re: C2 Idler Arm

Don,
Do you have a pic of the part that mounts to the frame? Are there any markings between the bolt holes?

Thanks

[Donald T.]

Re: C2 Idler Arm

Rob,

I don't have any other pics. I don't have the idler arm handy either, but if I recall correctly is also has the 135 stamped on the mounting arm as you describe. If it is an original from a 69, then it would be identical to a 65. The important thing is that it has the GM and part number cast as pictured and no grease fittings. From your description, it should be correct for your 65.

[Stephen L.]

Re: C2 Idler Arm

Original 67 idler arm.

[Rob M.]

Re: C2 Idler Arm

Steve - I can't see the picture. Can you email it to me?

Thanks

[Joe L.]

Re: C2 Idler Arm

Don------

It looks correct to me except for one thing: the slotted nut should be "plain" finish, not zinc plated. Of course, if it were me I'd prefer the zinc plated version EXCEPT for one other thing: virtually all of the zinc plated, slotted nuts on the market today are ungraded steel nuts. The original nut used for the application for 63-75 was GM-286M (SAE grade 5). For critical fasteners, I would not use any of unknown material grade.