C4 Rack Fittings

[Bluegrass Trifive]

Does anyone know what size the male fittings are on a C4 Corvette Rack? They seem to be 12mm x 1.25 AN Style but I'm not for sure. Headed to the Parker Store tomorrow.

[chevynut]

They are metric and I believe they're 45 degree fittings not 37 degree AN fittings. If you find anything let me know. I'd love to replace my hardlines with some -4AN hoses and correct hose ends. Did you rotate the rack cylinder?

[Bluegrass Trifive]

They are metric and I believe they're 45 degree fittings not 37 degree AN fittings. If you find anything let me know. I'd love to replace my hardlines with some -4AN hoses and correct hose ends. Did you rotate the rack cylinder? -4 hose is my goal as well. I think I may have found something but not sure. I do plan to rotate it. I haven't taken the rack apart yet to know but is it not possible to machine the fitting out and retap for a std fitting? I'll keep you posted on what I find.Thanks

[WagonCrazy]

I went with stainless hard lines, and had a local shop tig weld a banjo fitting on the end of one...
I'm sure that's metric as Cnut has said, and I can't remember what size. Would have to find the receipt and it's been a few years now since I had this done.
I also "clocked" the rack to get the bottom pulley on the LS1 to fit properly forward.

3906 3907

[chevynut]

The steering shaft end of the rack can be fitted with banjo fittings or metric to AN adapters and you can connect a -4AN hose to those. It's the cylinder end that's the problem. If there was some sort of -4AN hose end that was 45 degree and had a metric nut, that would do it. But I have not been able to find one. Maybe there's something available "across the pond" since we can't seem to get away from english/SAE stuff and move fully to metric.

[Rick_L]

Have you looked at an Aeroquip industrial catalog? They may have what you want.

[chevynut]

Rick, I have tried searching lots of places but it's pretty confusing. The catalogs have ends for different kinds of hoses and with different nuts. I guess the first thing we need to do is to determine the exact threads and flare angle on the rack fittings. I know they're metric and probably 12mm as Bluegrass said, but I'm not sure if they're 37 degree or 45 degree. Then I think the thing to do is to call someone like Parker, Tubes N Hoses, Inline Tube, or Aeroquip and see what they have that will work. It's possible that even some of the brake line suppliers can make them up. Crimped end fittings would be fine with me.

[Bluegrass Trifive]

Rick, I have tried searching lots of places but it's pretty confusing. The catalogs have ends for different kinds of hoses and with different nuts. I guess the first thing we need to do is to determine the exact threads and flare angle on the rack fittings. I know they're metric and probably 12mm as Bluegrass said, but I'm not sure if they're 37 degree or 45 degree. Then I think the thing to do is to call someone like Parker, Tubes N Hoses, Inline Tube, or Aeroquip and see what they have that will work. It's possible that even some of the brake line suppliers can make them up. Crimped end fittings would be fine with me. Well I've spent a ton of time online, at the Parker Store and a couple of other stores and have finally determined that nobody makes an off the shelve remedy. It is a M12 x 1.25 thread with a 45 degree seat angle. I found 45 degree seat fittings with standard threads or metric threads with 37 degree seat but not together. I even found -4 hose fittings with M12 x 1.25 threads but of course they had the 37 degree seat. I'm currently getting a quote from a fitting company that I deal with at work to make some custom ones. When I get the price I'll let you know and if anyone else is interested I can add to my order.

[chevynut]

I wonder if a guy could just machine the 37 degree seat in the fitting to a 45 degree seat, or somehow machine the rack fittings to 37 degree. I have heard of fittings that work with either angle, having two seats in them. It seems like a 45 degree cutter could be used inside the fitting to change the angle. It's not that big of a change.

Where did you find the -4 hose fittings with the M12 threads? Are they for teflon-lined stainless braided hose?

[Bluegrass Trifive]

I wonder if a guy could just machine the 37 degree seat in the fitting to a 45 degree seat, or somehow machine the rack fittings to 37 degree. I have heard of fittings that work with either angle, having two seats in them. It seems like a 45 degree cutter could be used inside the fitting to change the angle. It's not that big of a change.

Where did you find the -4 hose fittings with the M12 threads? Are they for teflon-lined stainless braided hose? The metric hose fittings for -4 hose are made by Mocal and the dealer I spoke to was BAT Inc in Sarasota Florida . Their web site does describe the -4 as being for a Teflon lined hose but the seat angle is 37 degrees and they're only described as 12mm and they could only tell me they "were sure" they're 1.25 thread pitch but nothing on paper. There are JIC fittings that have both 37 degree and the SAE 45 degree seats but not that I could find in metric thread. In regards to modification of something to make it work I wondered the same thing, in fact I ordered a end mill ground down to the tap drill diameter for the M12 with a 45 degree end to cut the seat as well, I'm gonna make something work. I'll keep you posted on my progress, I don't give up too easily!