Ford 9" and LS1 brakes - I messed up

[67rstbkt]

Hoping you guys can help me out of this mess I think I created. I narrowed a 9" Ford I had and used Moser 7900 housing ends. These maintain the Ford bearing size while using the GM pattern for the brakes. My plan was to use LS1 Camaro/Firebird brakes. While talking with QT performance about ordering axles, he said:

"I hate to inform you but the ends you need for those brakes are Part # 7900FM. The difference between these ends and the ones you have is the 7900FM are called "flush mount" as they let the axle bearing sit flush in the housing end. The bearing bore is deeper. The ends you have will leave the bearing sticking out 1/8", which is common for the 9" style bolt in axles. The factory 93-02 Camaro backing plate will need to sit flush against the housing end to work properly. One might be able to carefully machine the bearing bore deeper to allow the bearing to fully seat."

I've put way more work into this rearend than I want to admit at this point, all the points for my 4 link are welded on, housing is completed. Any suggestions on how I can salvage this? Can I remove the 1/8" from the brake backing plate? Has anyone else run into this issue? Any advice appreciated

[srh3trinity]

Either call tobin and see if he has a solution or maybe machine a spacer that would give you a flat surface.

[67rstbkt]

Either call tobin and see if he has a solution or maybe machine a spacer that would give you a flat surface.

Thanks, I did some preliminary mocking up last night and got some measurements off a 98 Camaro. Looks like if I add in a 1/8" spacer, my new axles will have to have an offset +3/8" from where the stock ones are. Even without the spacing, looks like I'll need a greater offset to fit these brakes. I'll get more accurate measurements and talk to the guys I'll be getting my axles from.

[CRead01]

I am not sure if this will work on the ls1 backing plates but on my regular 10 bolt drum backing plates I had the center machined out to a larger dia. and put them directly to the housing ends.

[Apogee]

I would think that you could just machine a counterbore in the back of LS1 backing plates to accommodate the bearing standout height of .105"...at least that's what I've measured it at, however do confirm that by measuring your housing end cbore depth and subtracting your bearing race width. Just to confirm, you're running the sealed ball bearings not the SET20 tapered roller bearings, right?

What's your axle/brake offset from the housing end to the face of the axle flange where the rotor mounts?

Tobin
KORE3

[67rstbkt]

I would think that you could just machine a counterbore in the back of LS1 backing plates to accommodate the bearing standout height of .105"...at least that's what I've measured it at, however do confirm that by measuring your housing end cbore depth and subtracting your bearing race width. Just to confirm, you're running the sealed ball bearings not the SET20 tapered roller bearings, right?

What's your axle/brake offset from the housing end to the face of the axle flange where the rotor mounts?

Tobin
KORE3

Thanks for the reply, Tobin. I'm running the tapered stock bearings. I'm still working on getting an accurate measurement on the axle/brake offset. With the stock Ford 9" axles I have right now, it appears to be roughly 2 1/4"
I will take some time and get an accurate measurement this weekend, I did not have enough time to do it last night.
The good news, I think, is that when I cut the housing I made it a little shorter than I needed figuring it's easier to space a wheel out a touch, so I have room to work with. I can get axles with a 2.5 or 2.75 offset and work with the exact spacing needed by adding shims. I guess I just need to make sure which one woul dwork best. I don't want to go 2.75 if the 2.5 will get me where I need to be.

I thought about machining out the backing plate, but had some concerns about compromising strength. There seems to be plenty of material there, but some others had mentioned that this backing plate was never really designed to act as a retainer and taking out even that little bit could be a concern.

[67rstbkt]

One more question on this regarding some other parameters:

1: the size of the axle flange (surface that the rotor will mate too) - The stock LS1 rotor appears to mount to a surface that is approximately 6 3/8" measured across, not diameter. Does the new axle need to be the same or can it be smaller? The axles I'm looking at are 5 3/4" across

2: the register - middle of the flange or hole in the center of the rotor. The rotor looks to be 2.775, the axle is 2.770. Is this ok being slightly smaller?

I know these two specs would fit since they are smaller than the full dimensions, just wondering if there is any reason why this would be a problem?

[Hammered]

I made up the 0.105" (12 gauge) with a spacer that also acts as a parking brake bracket. I have drawings posted here: http://1967firebird.atwebpages.com/chassis3.php

You want the rotor centered in the abutment bracket so I would mount everything up and see what axle offset gives you that.

[67rstbkt]

I made up the 0.105" (12 gauge) with a spacer that also acts as a parking brake bracket. I have drawings posted here: http://1967firebird.atwebpages.com/chassis3.php

You want the rotor centered in the abutment bracket so I would mount everything up and see what axle offset gives you that.

Thanks for the link, that looks awesome!

[67rstbkt]

Just want to say thanks for all the help, I've measured about a million times (at least it feels like that) and ordered my axles today. I have two ways I can go; first is to use the Camaro rotor, the second is to use the Corvette rotor. The Camaro rotor looks like it should work with my setup, but I may need to have that .105 machined out of the backing plate to make it perfect. With the Corvette rotor, I would have to space the backing plate out towards the rotor, so no machining. I'll decide when I get the axles and let you guys know what I went with.

[Rhino]

If you haven't ordered axles yet you've got a plethora of choices available to you. It all really comes down to what rotor you actually want to use.
If you were to use a 1/8" spacer between the housing end and the brake backing plate you'd be emulating the flush bearing end. Using the Camaro rotor would give you a "standard" that you could rely to whoever's making your axles.
When I ordered my setup from moser I gave them my flange to flange width and had them set it up for a standard 4th gen brake setup. You could do the same, but your housing length measurement would include the width of the spacers.

[67rstbkt]

Just wanted to take a minute to update this with my solution. I ended up using the full Camaro setup (aka LS1 brakes) with the corvette caliper.

I ordered my new axles with a 2.5" offset, which worked out well with the new brakes.

To solve the problem of the Ford style bearing hanging out of the housing end, I took the backing plates to a machine shop and had them remove .105
They made a perfect cut and I like that the seal sits inside a recess rather than a plate sit flat against it.

If someone else decides to run this style brake on a Ford 9" with GM ends, I would suggest getting the flush mount housing ends so you do not have to worry about getting the backing plates machined.

I also reversed the sides so that the calipers are located towards the rear instead of the foward side of the wheel. There is a little more space for the large caliper clocking it this way. Also, this will change the e-brake cable configuration to a forward pull.

The rubber boots on the backside were very well worn and I could not find just rubber boots, so I used the rubber from my old B&M shifter to make new ones. I just cut a slit for the lever, slid over the new rubber, re-attached the factory cover, then trimmed off the excess (I don't have a picture of it).

[Apogee]

Just FYI, you can buy just the parking brake boots here if you like: http://www.rmsautoparts.com/proddetail.php?prod=0FH-Brake-Boot

Tobin
KORE3

[67rstbkt]

Just FYI, you can buy just the parking brake boots here if you like: http://www.rmsautoparts.com/proddetail.php?prod=0FH-Brake-Boot

Tobin
KORE3

Thanks Tobin, I checked them out last week and it looks like they are going out of business/no more orders

[67rstbkt]

Just FYI, you can buy just the parking brake boots here if you like: http://www.rmsautoparts.com/proddetail.php?prod=0FH-Brake-Boot

Tobin
KORE3

I've been looking for t-bolts longer than the stock Ford ones I have, do you know where I can find some of those?

Thanks!

[Apogee]

I've been looking for t-bolts longer than the stock Ford ones I have, do you know where I can find some of those?

Thanks!

Not a lot of T-bolt options, but call Currie Enterprises and see what they can offer as they'll generally have it if it was ever made for a factory 9". That said, 1-3/8" is the longest I've found IIRC, so we generally just use a hex head cap screw and grind a flat on one side so that they'll slide in next to the housing end and not rotate. Alternatively, I've seen people use socket head cap screws and just hold them with a wrench when tightening the retaining bolt nuts.

Tobin
KORE3

[67rstbkt]

Not a lot of T-bolt options, but call Currie Enterprises and see what they can offer as they'll generally have it if it was ever made for a factory 9". That said, 1-3/8" is the longest I've found IIRC, so we generally just use a hex head cap screw and grind a flat on one side so that they'll slide in next to the housing end and not rotate. Alternatively, I've seen people use socket head cap screws and just hold them with a wrench when tightening the retaining bolt nuts.

Tobin
KORE3

Thanks! I have a good amount of thread engagement with the current t-bolts, but I would feel better if I had another 1/4" or so there. I'll keep looking in the meantime - I'll probably swap them out for something before I get the rest of the brake stuff mounted up.