LS1 rear discs on a 9" ford with GM ends

[67CamNKC]

I have a brand new big bearing ford 9" housing with GM ends. I will be using LS1 Camaro rear brakes. I set one of the new axle assemblies in. The bearing slides in good. The outer seal looks like it might not seat all the way in the axle tube on the outer edge. Will I need to run a spacer between the backing plate and the housing flange to allow for this? Or should that seal go all the way in? I'm not ready to knock the seal in just yet.

[67CamNKC]

Here are pictures to describe what I'm talking about. It looks like the seal will be sticking out about an eighth of an inch. I've read many posts about spacers being used, just wasn't sure if this was why.

Thanks

[BBPanel]

Shannon, perhaps there is more than one way to do this - I have the same housing ends from Moser on my 9" and this is the order of the bearings, etc. I have not pressed the bearing and spacer on yet, the LS1 backing plate needs to go on first. My seal goes in the housing first. Notice the diameter of my seal compared to yours - I wasn't aware of an outside seal. In addition, the backing plate will seat the bearing in the housing and should sit up flush to the housing end by virtue of the t-bolts - I don't see how yours is going to do that with the seal protruding from the housing end. Did you get all of your parts from one vendor?

[67CamNKC]

I paid for an upgrade to Moser "hobby stock" axles. They recommended them for autocross or road courses. It made the outer axle and flange thicker. Everything came directly from Moser. Mine also came with inner seals with the t-bolts, but looks like thats a kit. I'll give them a call on Monday.

[big gear head]

These are different bearings. Shannon has the tapered roller bearings and Bob has the sealed ball bearings. They are set up different. The tapered roller bearings take side loads better for auto cross and road racing. These bearings require oil from the differential, so the inner seal can not be used. The sealed ball bearings have grease packed inside them, so they need no oil.

The Hobby Stock axles are larger where the bearing presses on. They use a bearing with a larger ID and the seal is also larger. The caliper brackets are going to need some machine work to fit correctly. I will contact Moser Monday and find out exactly what modifications are going to be needed.

[BBPanel]

Very interesting - I had no idea. BGH, I asked Moser about the spacer they provided and they said it was for the brake spacing. The bearing is a pressed fit and therefore I assume will not move, the backing plate then seats the bearing into the housing against the upset lip. How can the axle position change in this scenario? I still don't understand what the spacer does. I also note Shannon's spacer has a taper on it and mine doesn't.

[Apogee]

How thick is the spacer they provided? It may just be to move the backing plate out slightly so that the brake offset dimension, the distance from the backing plate mounting point to the outside of the axle shaft flange, is correct for the brakes that you are running. This also sets the parking brake engagement depth.

The SET20 tapered roller bearings are wider and stand out of the housing end more than the equivalent ball-bearings. Most people who choose to run the GM/Ford Hybrid housing ends intending to run LS1 rear brakes opt for the Moser #7900FM housing end where the "FM" stands for "Flush Mount", but only applies to the narrower ball bearings. That way the bearing is flush with the housing end and the LS1 backing plate can serve as the retainer without any spacer or modifications required. I can only guess that spacing the backing plate out will cause issues with caliper/rotor alignment as well as parking brake engagement depth. You could alwasy machine the backing plates with a counter bore to account for the additional stick-out dimension of the SET20 bearings. Keep in mind that you need a certain amount of "crush" on the seal since the retainer is contacting the bearing through the seal and there are small rubber ridges inside the seal that need to be compressed. I would probably use whatever specs Moser recommends.

Tobin
KORE3

[67CamNKC]

I will contact Moser Monday and find out exactly what modifications are going to be needed.

Freddie, when you call Moser, ask them how much of the seal should be sticking out. This way I know how much to machine my backing plates.

[BBPanel]

I guess that is what confuses me - I do have the flush mount housing and the narrow bearing - therefore I expect the backing plate to sit up against the housing end. In Shannon's case I can see where there will be some machining required to get the backing plate to sit flush - I'm a little surprised this wasn't communicated to him since most of us don't have that capability in our backyard shops.

The machined lip on the axle where the bearing seats determines the brake offset. Given that, I don't see how the spacer does anything unless it crushes the seal (and I believe you were referring to Shannon's situation when you spoke of a "crush"?) - I can measure the spacer depth and see where its going to sit relative to the seal but I don't see how it can affect/control the brake offset spacing - and if it does that is not a positive means of retaining the axle and bearing and the backing plate will not be up against the housing end.

Looks like this thread is turning into two different discussions - sorry Shannon, didn't think it was going to turn out that way - but I've certainly learned something from your situation.

How thick is the spacer they provided? It may just be to move the backing plate out slightly so that the brake offset dimension, the distance from the backing plate mounting point to the outside of the axle shaft flange, is correct for the brakes that you are running. This also sets the parking brake engagement depth.

... Most people who choose to run the GM/Ford Hybrid housing ends intending to run LS1 rear brakes opt for the Moser #7900FM housing end where the "FM" stands for "Flush Mount", but only applies to the narrower ball bearings. That way the bearing is flush with the housing end and the LS1 backing plate can serve as the retainer without any spacer or modifications required. .... Keep in mind that you need a certain amount of "crush" on the seal since the retainer is contacting the bearing through the seal and there are small rubber ridges inside the seal that need to be compressed. ... Tobin KORE3

[67CamNKC]

I'm a little surprised this wasn't communicated to him since most of us don't have that capability in our backyard shops.

BBP, no problem. When I was talking to Freddie, he mentioned machining before I bought the upgrade that this might be the case. I was hoping I didn't have to but, looks like I will. I do have the capability to machine the backing plates, I just want to get the depth right. I've never assembled a 9" with this configuration and wanted to be sure how to assemble it. Mine shouldn't have come with everything installed. My concerns now are getting everything off and the new parts into the correct position. I just don't want to have to take it on/off several times to get the machined depth right.

[BBPanel]

BBP, no problem. When I was talking to Freddie, he mentioned machining before I bought the upgrade that this might be the case ...... Mine shouldn't have come with everything installed. My concerns now are getting everything off and the new parts into the correct position. ...

I thought you had purchased directly from Moser - my experience with them has been pretty good but they don't elaborate much - perhaps they assume we/I know more than we really do.

It looks like you don't need the inner seal like I do - but what about the spacer - do you need it also? And what does it do - it looks thinner than mine but pictures can be deceiving. Taking things on and off is my concern also - that is why I'm still trying to determine the real need for the spacer.

[big gear head]

What you are calling a spacer is not a spacer, but a retainer. This is pressed on after the bearing to help hold it in place so that it doesn't slip off under heavy side loads. I have seen these bearings pull off of axles before even with this retainer. I have also seen axles that were threaded in this area and had a screw on retainer instead of a press on retainer.

[BBPanel]

What you are calling a spacer is not a spacer, but a retainer. This is pressed on after the bearing to help hold it in place so that it doesn't slip off under heavy side loads. I have seen these bearings pull off of axles before even with this retainer. I have also seen axles that were threaded in this area and had a screw on retainer instead of a press on retainer.

Thank you for an explanation that makes sense - just for the record Moser called it a spacer so I did also. I assume I shouldn't have any issues in a street car application losing a bearing.

[big gear head]

http://www.moserengineering.com/mose...maroBrakes.pdf
Here are the instructions for installing the F body brakes with the flush mount ends. These instructions are for the sealed ball bearings, and it shows the spacer. The spacer and retainer (Moser calls it a press ring) are not the same thing. This spacer is for the '93 to '97 brakes and should not be used for the '98 to '02 brakes. The spacer was used for the earlier brakes becasue GM didn't hold a close spec on the brakes for these years and sometimes the spacer is needed to offset the axle for proper alignment. Unfortunately these instructions don't tell anything about machining the bracket for the tapered roller bearings.

Shannon, I have a new set of bearings being shipped to you. When they get there put them in the housing and get some measurements off of them so that you will now what needs to be done to the brackets. I don't have anything here that I can measure to help you with this, and I wasn't able to get more information from Moser about it. They told me that these bearings should also fit flush, but it looks like yours don't fit that way. The best way to do this is to measure it when you put the bearings and seals in the housing. You are going to want the bracket to fit tight against the seal so that it holds the bearing tight in the housing. I know that this isn't exactly great service and I wish I could help more. If you still have questions please let me know.

[67CamNKC]

As soon as I receive the bearings, I'll take some measurements.

[BBPanel]

http://www.moserengineering.com/mose...maroBrakes.pdf
Here are the instructions for installing the F body brakes with the flush mount ends. These instructions are for the sealed ball bearings, and it shows the spacer. The spacer and retainer (Moser calls it a press ring) are not the same thing. This spacer is for the '93 to '97 brakes and should not be used for the '98 to '02 brakes. ...

Thank you again for providing information that Moser should have - but then again w/o the 1/8" spacer explanation plus it shows a bearing w/an o-ring, it would have just raised more questions. I assume the o-ringed bearing is an extra seal or was it the only seal at one time? Mine is not o-ringed nor did I get the 1/8" spacers (I assume they knew I don't need them).

[big gear head]

I hadn't noticed that you have bearings with no O ring. That's a plus to me. The O ring is a pain and just about useless. Yes, it was the only seal that they used for a while. I always use the seals that you have and leave the O rings off. If you have '98 or later brakes then you don't need the spacers.

[BBPanel]

Thanks again for your help. Shannon - once you have machined the backing plates post them up if you don't mind - would like to see them.

[67CamNKC]

As soon as I receive the bearings, I'll get it machined and post pics. I was doing some measuring last night and looks like I'll need to machine a groove about .070" wide by .100" deep, but I'll confirm.

There is a rubber edge on the bearing side of the seal that looks like it needs compressed. I may get an extra seal locally just so I can set the bearing in and press the seal in and be sure.

[big gear head]

Can you use the bearings that are on the axles now for testing? Put some clamps on them and see how much they compress and then measure the thickness. Before you try to remove these beairngs take a chisel and a big hammer and make deep cut marks across the retainer ring all the way around it. This will loosen the retainer so that it will come off easier.