Rear Brake Line 57

[valhalla 4771]

Checking to see if I'm reading the manual correctly and that the previous owner kluged up a fastener. Area in question is the brake line junction block that is attached to the left half of the rear axle. From this block brake lines feed to each rear wheel. When taking it apart I found the block was attached directly to the axle with a hollow bolt...hollow all the way through. It has a hex head that allows me to screw the bolt into the axle. The hollow bolt then extends another 1/2" above the hex head. There was a homemade cap (not air/liquid tight) crimped on the top end. Looking at the illustrated manual I see a regular old 7/16" 20 x 1" bolt. I thought I better check to verify this hollow bolt has no function, like maybe some sort of inspection peephole into the axle????Seems unlikely, but I'm a total novice....

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[Douglemmo]

Checking to see if I'm reading the manual correctly and that the previous owner kluged up a fastener. Area in question is the brake line junction block that is attached to the left half of the rear axle. From this block brake lines feed to each rear wheel. When taking it apart I found the block was attached directly to the axle with a hollow bolt...hollow all the way through. It has a hex head that allows me to screw the bolt into the axle. The hollow bolt then extends another 1/2" above the hex head. There was a homemade cap (not air/liquid tight) crimped on the top end. Looking at the illustrated manual I see a regular old 7/16" 20 x 1" bolt. I thought I better check to verify this hollow bolt has no function, like maybe some sort of inspection peephole into the axle????Seems unlikely, but I'm a total novice....

 

[Douglemmo]

The hollow bolt is the vent for the rear end housing and is suppose to be there.

 

[valhalla 4771]

Thanks. Good thing I asked. I finally found this bolt shown in the illustrated manual on the drawing labeled 57/58 Ford brake system, .but not on the drawing labeled 55-57 typical Thunderbird brake system. Furthermore, of the half dozen supplier catalogs for 55-57 only 1 (CASCO) shows this part on their brake system drawings...and it appears no one has this bolt for sale. I see only a solid bolt that everyone carries. No venting.

So my question du jour....is this vent bolt necessary?

 

[Douglemmo]

It is the old story - it depends. I'd rater put it in and not worry about oil getting blown out of the axel seals " if the rear end gets hot enough to build up pressure". You could drill a hole through a bolt or you could look in an early Mustang parts catalog. The early Mustangs have the same arrange using a vent bolt to attach the brake line junction block to the rear end housing.

Good luck,
Doug

 

[valhalla 4771]

Ok. I’ll find one somewhere.
Does the top of the bolt need a non-airtight cap? Or hose going somewhere? Or just left open?

 

[Douglemmo]

Either a non airtight cap or what the Mustangs do is run a rubber tube to a nearby hole in the frame. But i guess it could just be a short tube that points down so dirt doesn't get in it.

 

[doug7740]

Checking to see if I'm reading the manual correctly and that the previous owner kluged up a fastener. Area in question is the brake line junction block that is attached to the left half of the rear axle. From this block brake lines feed to each rear wheel. When taking it apart I found the block was attached directly to the axle with a hollow bolt...hollow all the way through. It has a hex head that allows me to screw the bolt into the axle. The hollow bolt then extends another 1/2" above the hex head. There was a homemade cap (not air/liquid tight) crimped on the top end. Looking at the illustrated manual I see a regular old 7/16" 20 x 1" bolt. I thought I better check to verify this hollow bolt has no function, like maybe some sort of inspection peephole into the axle????Seems unlikely, but I'm a total novice....

On the early 1957 model, the brass block was attached to a bracket welded to the axle housing using a solid bolt. The vent was screwed into the axle housing inboard of the bracket. Around November or December 1956, the junction block was then held to the rear axle tube using a longer hollow vent bolt.

The attached information is from the Thunderbird Restoration Details and Specifications Manual.

doug7740
1955 Thunderbird Blue