C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

[Scott S.]

Car is a 1967 small block, the AIM section for these parts is UPC 3, sheet A5 (page 159 in some versions).

One of my front stabilizer bar brackets (GM #3742246) with the "C" stamp has survived. I bought NOS rubber bushings (GM #3817573) but they look too small compared to the bracket (side to side), too small of an inner diameter compared to the thickness of the stabilizer bar, and too small compared to the old rubber bushing.

I understand that they will bulge out (some) when compressed during installation.

Is this how they are supposed to look when new, or did I get the wrong size bushings? The circumference of the front stabilizer bar is 2-1/2", using a tape measure. New rubber bushings on the left, one very tired bushing on the right.

[Scott S.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

A few more pictures, first with a new bushing in the bracket, then with the old bushing.

[Joe L.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

A few more pictures, first with a new bushing in the bracket, then with the old bushing.

Scott------


The new bushings you have appear exactly as they should. They will compress into the retainers and around the bar.

[John H.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

I bought NOS rubber bushings (GM #3817573) but they look too small compared to the bracket (side to side), too small of an inner diameter compared to the thickness of the stabilizer bar, and too small compared to the old rubber bushing.

Scott -

The plant used an overhead air-powered fixture to compress the bushings and brackets against the frame while they installed the nuts and bolts. You'll have to use a pair of longer bolts to make the attachment; torque them fully, then remove them one at a time and replace them with the correct-length bolts.

As Joe noted, your parts are correct.

[Scott S.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Joe and John, thank you both for the replies.

The JGs and archive searches show that the bolts (GM 3784303) used with the bushing brackets (GM 3742246) are Cad-plated, often seen with the Anchor headmark. The pictures below are from a 1967 survivor (427) that we examined during the morning session at the McDorman / NCRS Midwest Queen City Regional last September.

These bolts look like black phos in the photos, but that could just be 43 years of dirt and grime. The best picture I can find to zoom in on appears to show the "E" headmark with three grade lines.

Pictures:
1) Front, RH
2) Front, RH
3) Front, LH
4) Rear, RH (best headmark shot I can find, looks like "E" with 3 lines)


What is typical factory production for this application, a Grade 2 bolt, or Grade 5 (or other)?

Pinch-point, or flat tip?

-

[Rich P.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Scott,
picture # 4 is from the rear sway bar bushing retainer from a BB car. The bolt in the picture is a pinch point recessed head with a captured flat washer, typically used for the hood hinge or female hood catch. This is not typical factory production. I would be willing to bet the farm that this is the longer version of the bolt (there was a 7/8" and a 1"). In my years of working on untouched original cars I have seen the assembly line workes "cheat" with different bolts in this location more than any other. If you would poll 66 427 HP car owners I would bet that more than a few had the sheet metal thread steering colum clamp bolt used here (63-66's used a different bolt than 67's)
You are correct the E bolts have black phophate plating. Thanks for the pictures as I see non typical things like this very very often.

Rich

[Rich P.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Scott,

very neat J-56 BB car. The chassie has been "cleaned" not restored but cleaned. The lower control arm busing retainers and bolts have no paint on them. It is a outstanding car buy any means. If you look closely at the J-56 caliper support brackets and attaching hardware they are dirty and it's hard to distinguish the different finishes. I'm willing to bet the rest of the frame look similar before a very through cleaning. I am not knocking this car in any way it is an outstanding original!!!! You just can't trust everything you see as untouched original for finishes. I'd like to know more about this car. Looks like a Marina blue 67.

Rich

[Scott S.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Thanks very much for the comments Rich, it was great to have the opportunity to attend the seminar. The car is a 1967 Marina Blue convertible (BB). It was up on a lift for most of the morning session, and I tried to take pictures of everything. This was last September, before I really began learning about things at the nuts & bolts level. I took lots of pictures, but I wasn't always aiming at the things that I'm interested in seeing now. I can usually find what I'm looking for in the pictures, but I don't always have the right angle or a close enough view to answer my questions.

As I learn more, I am getting a better understanding of what to look for... and with the benefit of hindsight, I'll try to take better pictures next time.

The afternoon session was on a survivor 1965 L79 coupe. Here are a few more pictures, our teacher is the busy guy on the phone in picture #4 (Mike Murray). I would like to take that seminar every day for a week if I could, Mike did a fantastic job.

[Scott S.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Rich, I forgot to ask in my last post. For "typical factory production", are the bolts (GM 3784303) to the front stabilizer bar "U" brackets Grade 2 with flat tips? That seems to be what the vendors are offering for this application, but I was expecting at least Grade 5 for something involved with the front suspension.

[Rich P.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Rich, I forgot to ask in my last post. For "typical factory production", are the bolts (GM 3784303) to the front stabilizer bar "U" brackets Grade 2 with flat tips? That seems to be what the vendors are offering for this application, but I was expecting at least Grade 5 for something involved with the front suspension.

Scott,

Typical factory production bolts for the U brackets on 63-67's are 5/16-18x7/8" Recessed hex with a captured split ring lock washer, flat tip grade 2 Anchor. Other headmarkings I have seen here ar E, E in a circle, GL, NL and RBW (the RBW's were grade 5 why I don't know) If you check, this bolt should also be called out for the battery tray to frame bolts (non A/C cars). Here again I have seen 3/4" bolts used for the battery tray but the AIM calls for the same bolt as the sway bar. The repro Anchor head bolt is very close but the way the recessed head transitions from the ridge to the flat is disched to much and can be spotted easily. All in all one of the better repro bolts out there.

Rich

[Scott S.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Scott,

Typical factory production bolts for the U brackets on 63-67's are 5/16-18x7/8" Recessed hex with a captured split ring lock washer, flat tip grade 2 Anchor. Other headmarkings I have seen here ar E, E in a circle, GL, NL and RBW (the RBW's were grade 5 why I don't know) If you check, this bolt should also be called out for the battery tray to frame bolts (non A/C cars). Here again I have seen 3/4" bolts used for the battery tray but the AIM calls for the same bolt as the sway bar. The repro Anchor head bolt is very close but the way the recessed head transitions from the ridge to the flat is disched to much and can be spotted easily. All in all one of the better repro bolts out there.

Rich

Thanks Rich. I just received the repro with Anchor headmark today, I think I see what you mean about the transition area, it almost looks "frosted" in a circle around the anchor symbol. Nothing a little road dirt won't hide

My '67 AIM shows different part numbers for the battery tray bolts (both w/C60 and without C60), and both have a different part number from the 3784303 stabilizer bar bracket bolt. My "mystery bolts" bag has two flat tip black phos RBW Gr5 indented hex bolts with captured split-lock washer, 5/16-18 x 7/8". At this point, I'm guessing that's either one short of three needed for the battery tray, or this car is an uncommon example that used RBW Gr5 bolts for the front stabilizer bar brackets, and I'm missing two of them.

I did find a good picture of a front stabilizer bracket bolt earlier today when I was looking for pictures of thermostat bolts for the other Thread. The picture below is from a '67 L79 convertible that was in the Car Corral at Carlisle last year. I crawled under the car to get this one.

As Jerry likes to say,

Having fun!

[Ronald L.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Scott,

Here is a picture of the partial picture I took 30+ years ago of the battery box bolt on a December 65 427 car, RBW was noted on all 4 bolts. This was the first time these bolts had been touched.

293kb file size limit???- when are we going to get to the 21st century?

On my later 66, same style, but the originals are E head marks.

I need to replace the original rubber in the sta bar so we'll have a look at those soon.

The reason they were usually a grade 2 is that when they snapped they were easy to drill out and replace.


Scott, since I could still add on to this...

The 66 front sta bar bracket bolts I have now that clearly have never been touched have a rusty anchor head mark on them. I bet I have to find one or two just in case - these snapped easy.

[Scott S.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

Thanks Ron, seems like engineering might have developed a better solution than using weak bolts to make it easier to fix when (not if?) they break

Also, I realize now that I was incorrect regarding the number of bolts referenced in my previous post as far as battery trays are concerned. My C60 battery tray has holes for six bolts, and from your post it sounds like the non-C60 battery tray requires only four bolts. Not so easy to tell from the drawings in the AIM sometimes.

[Rich P.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

396 and A/C cars use 6 bolts for the battery tray. 5/16-24 thread x 7/8". Recessed hex with D in circles self tapping/thread starting tip. Excactly like the spare tire tub mounting bolts just twice as long.

All others used 4 coarse thread bolts.

Rich

[Scott S.]

Re: C2 front sway bar / stabilizer bar Brackets, Bushings & Bolts

396 and A/C cars use 6 bolts for the battery tray. 5/16-24 thread x 7/8". Recessed hex with D in circles self tapping/thread starting tip. Excactly like the spare tire tub mounting bolts just twice as long.

All others used 4 coarse thread bolts.

Rich

Rich,

It appears from the AIM that the original configuration for non-C60 battery tray bolts is a sems bolt ("Screw Asm.", with attached regular lock washer?) and four "P. Washers" (does "P." mean "plain" or flat washer?)

The C60 battery tray bolts are not sems, but plain bolts with a separate "P. Washer" (uses the four from non-C60 and adds two so all six bolts have a washer on the C60 battery tray).

I have exactly six bolts in my "mystery bolts" bag that are very close to your description, and so far I have not been able to figure out where they go. They are black phos indented hex head bolts, flat tip. There is a very slight taper to the threads at the very tip (last 2 threads or so).

Five of them have a slightly off-center "E" headmark, and the last one has three concentric circles. No grade lines on any of them. They are not quite the same as your description in the dimensions though. These bolts (pictures below) measure 1/2" across the flats and are 5/16-18 x 23/32" (just barely under 3/4" long, measuring from under the head to the tip).

If these are not my C60 battery tray bolts, do you know what they are or where they go?