Rear brake brass block and hose assembly bolt (12 bolt posi)

[HawkX66]

On mine, and several others I've heard of, there is a different bolt other than the other 11 on the diff housing. It's the bolt that holds the brass block and rubber hose assembly where it goes from the pumpkin to the floor. In the AIM (UPC 5, B3.), it says it's just part of the axle assembly and doesn't show that it's different. Mine still works, but it's pretty rounded. The other 11 are good. The biggest difference I see is that it doesn't have the wide, washer like base like the other diff bolts. Anyone know the specs on this one? Is there a part number out there for it so I can cross ref the AMK book or somewhere else?

 

[JohnZ]

On mine, and several others I've heard of, there is a different bolt other than the other 11 on the diff housing. It's the bolt that holds the brass block and rubber hose assembly where it goes from the pumpkin to the floor. In the AIM (UPC 5, B3.), it says it's just part of the axle assembly and doesn't show that it's different. Mine still works, but it's pretty rounded. The other 11 are good. The biggest difference I see is that it doesn't have the wide, washer like base like the other diff bolts. Anyone know the specs on this one? Is there a part number out there for it so I can cross ref the AMK book or somewhere else?

 

There's no indication that a separate bolt was released for that location - if it was, there would be an item number and part number in the "H.D. Axle" view for it. I think you're seeing the result of "Bubba" making a substitution.

[zman1969]

I recently bought a 69 12 bolt that was a survivor -complete -still had date codes on brake adjuster levers and that cover bolt had a captured washer bolt for the brake line bracket I assumed was correct- rest of cover bolts did not
I know John is the man in the know ... any others out here?

[Hans L]

Here's what mine looks like.  I did not remove any of the differential rear cover bolts, other than this one and used the original when I re-installed the brake line bracket and clip.   

[HawkX66]

Thanks guys. Although not near as purdy as yours, mine looks like yours also Hans. I've seen a few other 12 bolts like that as well. My rear end was like yours Rich, unmolested. Mine had never been out of my car and has all original gears, brake hardware etc. Are both of yours late 69 builds by any chance.

[Hans L]

Dave -

The build date of my Z is 04B, Van Nuys.  The axle date/code is:  BV0403G1.     So I'd say it's a mid-year build, not late. 

Seems to me you have to have the smaller flanged bolt head otherwise it doesn't appear it would clear the bracket upon tightening. 

Hans

[HawkX66]

Dave -

The build date of my Z is 04B, Van Nuys.  The axle date/code is:  BV0403G1.     So I'd say it's a mid-year build, not late. 

Seems to me you have to have the smaller flanged bolt head otherwise it doesn't appear it would clear the bracket upon tightening. 

Hans

I agree Hans. The larger bolts don't seem to fit right. The smaller bolts fit correctly. I think if we looked, a lot more 1st gens would be the same way. Your Z is Van Nuys, mid year. Mine is Norwood, late year. I think it's way too coincidental that several of us have the same bolt on that bracket. This wouldn't be the first time the AIM has missed something.

[68camaroz28]

Here is a April 69 12 bolt out of a 69Z (restoration) showing the original hardware. Yes that bolt utilized there had no shoulder and had a washer.


RSC bolt!


My 68 used a different bolt as well.

[HawkX66]

 Great pics, thanks for posting them. I'd say it's safe to assume we've confirmed that the bracket used the bolt with the washer not a regular 12 bolt style bolt.

[HawkX66]

I happened to run across an ad over on YSC for 12 bolt posi diff cover bolts. Here's a couple more nice pics with the different brake line bracket bolt:

http://www.yenko.net/ubbthreads/ubbthreads.php/ubb/showflat/Number/630879/gonew/1/e-marked-12-bolt-cover-bolts#UNREAD

[Hans L]

Good to hear the different bolt in rear axle cover has been verified.   I also confirmed that mine has the washer underneath the bolt as well.

Question - what would be the correct finish for just that one unique bolt in the rear end cover plate?   

Natural/phosphated or black paint?   I assumed black paint as I assumed the bolt was in place when the axle assembly was painted. 

But the brake line/boss support bracket was added after paint - so was the bolt added after paint as well and should be natural/phosphated??

[68camaroz28]

Good to hear the different bolt in rear axle cover has been verified.   I also confirmed that mine has the washer underneath the bolt as well.

Question - what would be the correct finish for just that one unique bolt in the rear end cover plate?   

Natural/phosphated or black paint?   I assumed black paint as I assumed the bolt was in place when the axle assembly was painted. 

But the brake line/boss support bracket was added after paint - so was the bolt added after paint as well and should be natural/phosphated??


Hans, great question and one that hopefully can be answered by an expert. I can confirm a different bolt was used primarily due to the normal shouldered bolt interfered with the radii of the bracket so a non-shouldered bolt and washer was used both in 68 and 69. Both 68 and 69 AIM call out to utilize existing bolt but there are other areas where there are mistakes so I made an assumption the bolt was changed. Might be correct or wrong...... How my 68Z rear looks currently.....

[HawkX66]

My opinion, and it's only based on an educated guess, is that yours is correct Chick. It looks like phosphate right? I wouldn't be surprised if the rear end assembly arrived as it's shown in the AIM and then the 12th bolt was removed to add the bracket and other bolt. Obviously that bracket wasn't on when the rear end was painted so either they left a bolt out during painting and shipping, which I seriously doubt, or they took a bolt out to install the bracket on the assembly line.
 Now let's talk about your brake line clip Chick. The one bolted up by your seat belt support in that pic. Are you sure that's correct? That's the clip that bolts to the torque box at the front of the rear leaf spring. It's for the dual fuel lines. If you look close I think you'll find it has a larger bend on one side than the other to accommodate the two different fuel line sizes. It looks like you also don't have anything bolted in the correct hole for the brake line clip. It's in the top left of that seat belt support. I keep forgetting your pic is of a 68. Is it different?
Here's a couple pics of what I'm talking about on my 69:

[67y2rs]

What is the length of the 11- shouldered cover plate bolts ? Thanks, Ed.

[68camaroz28]

Now let's talk about your brake line clip Chick. The one bolted up by your seat belt support in that pic. Are you sure that's correct? That's the clip that bolts to the torque box at the front of the rear leaf spring. It's for the dual fuel lines. If you look close I think you'll find it has a larger bend on one side than the other to accommodate the two different fuel line sizes. It looks like you also don't have anything bolted in the correct hole for the brake line clip. It's in the top left of that seat belt support. I keep forgetting your pic is of a 68. Is it different?
Here's a couple pics of what I'm talking about on my 69:

Yes, the bolt and washer holding the brake bracket on the rear is gray phosphate.
Concerning the other brake line clip your questioning Dave, I have not studied 69 but for 68 its what was on our car and on my friends 68Z survivor. I went into detail on this in my build thread even showing a picture of the 68Z survivor clip/screw. What I've found is the use of the 3886522 clip with 3841230 screw and have that marked in my AIM.