How to: Narrow a 9" and add LS1 brakes (Write-Up)

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67rstbkt

G-Body Guru
Sep 30, 2010
556
18
Reno, Nevada
Decided to share this here as it might be useful to some. Around this time last year I decided to narrow a Ford 9" for my 67 Firebird. Although not a g-body, the same principles apply. Also, if anyone is interested in fitting the LS-1 brakes on their Ford rear....read on.

Before I get into it I should mention that unless you have a Ford 9 (or some other rear-end) laying around, I did not really save much over buying a manufactured to fit housing. Also, try to figure out the offset needed for the brakes you will be using first. This will save you a lot of time and frustration later on, trust me.

I started with a late 70's ( I believe) Ford F-series truck 9" housing. I traded an unused home gym for it, so in my mind it was basically free.

Step 1 was to compare the 9" to my old 8.5 GM housing. I set them up on jack stands and later built a jig out of 2x4's to line them both up. This allowed me to compare center to center and overall length. You will most likely end up cutting uneven amounts off to match the pinion centerline. Because I had leaf spring perches, it was easier to match my pinion angle pinion. On a g-body rear, I would use an angle finder to compare the angles when welding your perches and control arm brackets back on.
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

Measure, measure, measure - I can't stress that enough. Measure and re-measure before you cut anything. As you can see in the second pic above, I removed all the previous bracketry. It's best to do this first. I used a large set of hose clamps to mark my cut lines then went at it with some fresh blades on my sawz-all. The blocks underneath were used to level out the assembly (my floor is not exactly level).

The picture shows the 2 housings after I cut off the ford ends and tacked on my new Moser ends. Make sure to check for differences in offset for the axles and brakes you will be using. The jig helped me to compare length and set my pinion angle. You may need to make adjustments, so be prepared to remove the new ends several times until you get it right. It is critical to use the welding jig to make certain you are lined up from side to side.

Here is my 2x4 jig:
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

I purchased new Moser housing ends for the 9", but you can re-use what you have if you feel like doing the clean-up work (and are using a Ford patterned brake system). The set cost about $100. I will also add that if you are using LS-1 F-body brakes (98-2002 Camaro/Firebird), it seems that the flush mount housing ends offered by Moser would work best. Turns out the stock Ford type ends I used make it so the bearing actually hangs out of the housing just slightly (just like the original), causing an interference and brake pad spacing issue with the LS1 setup.

The next step of this process is to get everything lined up perfectly. To do this, you will need a jig. You can find them on ebay for around $100 or you can do like I did and borrow it from a buddy. The jig consists of 4 slugs - 2 for the carrier and 2 for the housing ends. You will also need a sturdy and properly sized steel bar to slide through the assembly.

Here are some pics of the jig I used:
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

On to the bracketry - Like I said, I used the 2x4 jig to locate the brackets where they needed to be. The brackets in the picture are the stock leaf spring bracket (lower) and the 4 link brackets (upper). My 4 link uses the original lower bracket to locate the lower links. I tacked that on first, then test fitted the axle in the car and took some pinion measurements to locate the top brackets. Use an angle finder if you are going to match your previous setup's pinion angle. Tack weld it all together and then you will need to use something heavy duty enough for the job. In other words, I would suggest something other than a 110 volt mig. Fortunately, I have a friend that works on industrial boilers. $100 and a few hours later, it was all welded together with an industrial strength stick welder. You will want a chamfer on the mating edges - the guy that welded mine did a root pass, cleaned it up, then did the finish weld. Expect to make numerous small changes to get everything to fit together. I had to grind the round portion of my brackets just a bit so they would fit the larger diameter tube of the Ford housing.

***EDIT***
Note on the final welding. Make sure that you do not build up too much heat on the axle tube and ends. You can actually warp the tubes when you weld the ends back on. Do the welding in stages - 1/4 to 1/2 way around the tube and let that side cool down before continuing.
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

Here it is painted:
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

On to the brakes - I was lucky enough to get a set of backing plates from L.A.X-RATED on this forum (Thanks!) The problem I ran into is related to the previously mentioned new housing ends (I used the same exact style that I cut off, except they are patterned to accept a GM brake backing plate). Because the bearing hangs out slightly, the caliper to pad spacing was off. There are only so many options on axle spacing unless you want to spend more on a totally custom setup. That's right, I could not use the original axles. Turns out you can only cut certain axles due to how some are tapered. Additionally, the bolt pattern and hub flange was incorrect.

I figured out a 2.5" offset on the axle works well for the brakes. Because I did not use the flush mount housing ends, I had to remove .105 from the rear of the backing plates. A local machine shop did this for me for around $100 (see a pattern here)

Here is what they removed (round recess on the rear of backing plate):
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

On my F-body, I also had an issue with space if I mounted the caliper the same as the donor (towards the front of the car). My solution was to reverse the backing plates and have the calipers towards the rear. This also changes the orientation of the e-brake so that the cable will now have to be configured to pull forward. I have some thoughts on this, but have not completed yet.
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

That's about the whole deal, here are some extra pics showing the axles and backing plates installed. When you order axles, make sure you know the hub and flange dimensions. There is only so much space on the inside of the rotor. I will try and remember to get the measurements and post them here when I have a chance. I'll add more if I think of anything else. Feel free to ask questions, I'll do my best to give you a good answer :)
 

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L.A.X-RATED

Royal Smart Person
Aug 25, 2010
1,384
83
Re: How to: Narrow a 9" and add LS1 brakes

hey buddy! glad you are getting around to installing the ls1 set-up!!!the 9" looks swwwweeet!!! looking forward to the progress/resto of tha bird 8) check out the homie mel(melman109) he has a sick *ss 9" with a c5/6 set-up,powdercoated and all that he was gonna use on his 68 maro but opted to use it on his 85 elco! im planning 2 9" rears for my 88 aero ss,and my 87 SS.i inherited 2 furds trucks,2wd-57 and a 58 f100's.one is standard the other auto.i plan on doing a quick resto on these,then find some buyers,and put my profit toward my aero.i wanted to ask you if the rear 9's from these trucks will work on the montes? along with the trucks i also have 2 extra 9's so thats why im wanting to verify.ill be using ls1 setups on them both as well :wink: heres a pic of the 57.
 

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67rstbkt

G-Body Guru
Thread starter
Sep 30, 2010
556
18
Reno, Nevada
Re: How to: Narrow a 9" and add LS1 brakes

L.A.X-RATED said:
hey buddy! glad you are getting around to installing the ls1 set-up!!!the 9" looks swwwweeet!!! looking forward to the progress/resto of tha bird 8) check out the homie mel(melman109) he has a sick *ss 9" with a c5/6 set-up,powdercoated and all that he was gonna use on his 68 maro but opted to use it on his 85 elco! im planning 2 9" rears for my 88 aero ss,and my 87 SS.i inherited 2 furds trucks,2wd-57 and a 58 f100's.one is standard the other auto.i plan on doing a quick resto on these,then find some buyers,and put my profit toward my aero.i wanted to ask you if the rear 9's from these trucks will work on the montes? along with the trucks i also have 2 extra 9's so thats why im wanting to verify.ill be using ls1 setups on them both as well :wink: heres a pic of the 57.

That's a sweet 57 - I'll check out melman109 when I have a sec. I'm using the C5/C6 setup in the front. The LS1 rear is basically exactly the same, except you can get the backing plate to fit (Corvette has a 3 hole flange). The main difference is the calipers, C5/6 are cast differently. I'm actually using the C5 calipers on the setup I got from you.
The 9's you have should work, but you might want to google it to make sure. I seriously would reconsider using them though - Quick Performance has some really good deals and like I said, I didn't really save much. Maybe $100-200 at the most when all was said and done. I'll update this thread with some more specs on the brakes, just have to gather it all up.
 
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