Technical Rear brake flex hose rotates

First time builder here. I am at mock-up phase and working on plumbing my brakes. I have all the parts, pieces, and tools to get it done, but I’m stuck thinking about the rear brake flex hose. Here is a pic of the setup so far:


Question is, when the “T” on the axle moves up and down with suspension travel, the hose rotates about 15-30 degrees within the bulkhead tab on the frame.



Here is the bulkhead tab and clip that I’m working with (all Speedway parts).



I’ve never done this before and I was not expecting the hose and hardline attached to it to rotate within the bulkhead like it is. What are the thoughts of experienced HAMBers?

A. It’s fine as-is. Rotation is expected and the adel clamps will prevent/limit rotation once all installed.
B. The bulkhead and/or axle mounting locations are not acceptable - attempt to find new location(s) so the hose will not rotate.
C. The bulkhead clip should prevent rotation. Either the clip setup is faulty or a bit of fabrication is needed to ensure the hose will not rotate within the bulkhead.
D. Other ideas?

I appreciate any and all feedback.

 

Old chassis clips were made like a socket to keep the hose secure....Your tabs probably just have a round hole in it....Go online to Rock Auto and check out the brake hose ends and you will see how they keep from rotating...

 

show us a picture of the end of the hose in the mounting tab, but no clip, so we can see what it looks like. Many hoses have some type of shape that prevents them from rotating, if the tab has the correct shaped hole.

A thicker tab may help, if there is no such locating thing on the hose. So the clip has more tension

 

Here is a pic of the disassembled hose, mounting tab, and clip. It’s just a circle all the way around…no locating flat spot or anything like that.


Further reference, the parts are speedway and claim to be compatible with each other.

 

looks like one of the round ones.

 

If it were me I'd locate the end of the hose that goes on the axle where I want it and secure it and then using the end of the hose that goes though the tab as a guide, mark a couple of spots (or more) to weld on a bit to create a flat that will keep the hose from turning. Just a bit of weld and file to fit and done.

I've always snagged the brackets/ tabs off door rigs that I scrap.

 

Once the solid brake line fitting is tightened into flex hose, any twist should occur in hose portion, behind crimp only. Yes most OEM hose and tab assemblies have a index tab or irregular shape to locate these components to prevent rotation. However I assume you are seeing the metal line twisting to some degree with the movement. I solved the problem with a '68 Chevy p/up rear hose , 14" long, and modified the location tab to match hose end shape. I don't see enough material on the your hose end to file a "flat" and add them add a weld bead to hole in tab and file to fit, but you could try.

 

The problem appears to me to be the wrong hose being used in that location.


I could be mistaken, but that hose and your use of it is the problem. It doesn't belong there as you have it shown. That's my opinion.

 

So location/routing as apposed to a hose indexes it’s self is the issue?

 

To be clear as crystal, that hose should be positioned to drop down from above then it isn't affected by rear end movement.

 

I guess the physics of how front spindles move makes that wrong as well?

 

I'd probably run the steel line back and around the corner some, mount the tab on the crossmember, and mount the hose close to the center of the axle. With hose in an "L" shape it can move up and down without trying to rotate.

You could also mount the hose further forward on the frame so it ran straight to the axle and just had to move up and down.

 

Noel brings up a good point , relocation of tab/ union point more towards rear ,may eliminate twist problem, try and see what happens, at least this guy is paying attention to details to prevent problems down the road.

 

Kinda like this.

 

Nobody else was concerned about the axle housing rotating 15 degrees as it moves through the suspension travel and how that might effect U joint life?

 

Your ears must have wobbled, Gene. It's the fitting at the end of the hose at the frame that's rotating a little bit when the axle moves straight up and down.

Once again, I learn one of the teeniest tiniest little things from you guys... but which are so important.
And I'm sure will save me grief.
Thank ya. Thank ya very much.

 

Put a weld bead where the red dot is. File it so that it sits up against one of the wrench flats on the hose fitting.

 

Agreed, but it might be easier to place a small piece if steel to provide a straight edge against the hex of the brake line thus enabling the added piece to be welded to the tab away from where the action is. Saves filing welds straight etc.

Chris

 

The hose mount on the frame needs to be directly over the mounting hole in the axle.(or vice-versa)
Brake hoses are not meant to be twisted.

 

Don't the front brake flex lines twist with suspension travel and steering?

 

Thank you all for the suggestions and ideas. Seems like my gut instinct was right and the hose should not be rotating at all inside the bulkhead fitting.

I would expect the flex line to have some twisting capacity in the hose between the crimps, though. I assume as long as the hose ribs are parallel or “in-line” and not looking like a Twizzler, it should function well for its entire intended service life. Is this a wrong assumption? Should the hose not be subjected to ANY rotational forces? Just lateral and/or horizontal movement?

 

A few have mentioned on this all ready. Think what a front brake hose is subject to.

 

Crotty, first let me compliment you on your beautiful workmanship on your project. As for your question, I think that you are over thinking your problem. You are going to have minimal up-down movement, probably only an inch or two and I do not think that it will affect anything. I would build it just as you have planned, (almost a copy of how I plumbed my Deuce roadster, except I used braided flex lines) with zero issues in over 50,000 miles.

 

so you do plan on running a ford oem style vent bolt?
have you managed to buy one yet?

also where are the inputs to the wheel cylinders?

 

Thank you! The credit must be directed to the frame builder Blackboard Hot Rods for what you see in the pictures of this thread. I am just trying to keep up the rest of the build to his caliber as best I can and ensure this rig is as safe and reliable as can be.

I appreciate your real-world experience with this flex set-up and it definitely comforts me knowing that you’ve had so many trouble-free miles.

 

I was not planning on using a vent bolt for the flex hose mount - just going to weld on a 7/16” bolt as a stud. I kinda like the idea of being able to stick my head under the rear end after a drive and if I see any moisture from that flex hose mounting point, I know it’s brake fluid and not from the axle vent.

The rear drum brake cylinders are located at the top of the axle, angled towards the rear of the vehicle.

 

I agree with 'woodiewagon46', your suspension is only working aprox 2'' at most times, so it shouldn't be a problem..
If it does concern you, how about drop a bit of weld on the mount hole, file it flat, and then file a corresponding flat on the hose (aligning it in the right direction)..

 

Thanks again for all the insight. I am going to modify the bulkhead as suggested in order to prevent the slight rotation of the hose. I may try and find a better location for the bulkhead and axle mount as well. I’ll revert back with pics of progress eventually (I work real slow….)

 

Very impressed: Agree, however, with the 'L' shape for hose theory: If the front brake hoses MUST twist from steering left & right, then they must.
If, however, a simplex bend in the hose that wouldn't force a twist would be a reachable (and preferable) option.
The already supreme execution of design/application having been accomplished dictates continued perfection.
(Whew! That sounded pretty...'final'.)