Rear hub with 928 bearing and increased offset, 928 Hybrid trailing arm, 944 brakes, extended hub offset, parking brak Options

[SGB]

Simply amazing. Wow that sweet. (IMG:style_emoticons/default/smile.gif)

[Wilhelm]

As the axle would be going into a deeper hole, the angle it could traverse before it contacted the side wall of the tube would be limited. I am using 911 axles and making an aluminum spacer that fits between the connection of the CV joint and the stub axle. This will place this connection back to the normal orientation and regain normal range of motion.

The bearing is held in place on 928s by a huge freakin internal circlip.

It probably would be expensive machine work if I farmed it out, however doing it myself is fun. Certainly more fun than sandblasting sheetmetal and fixing rust!

[Todd Enlund]

Damn, dude... that rocks. (IMG:style_emoticons/default/aktion035.gif)

[Wilhelm]

Forgot to add this should anyone else be interested in making one. Truly the only critical dimensions are the bearing bore 84.933mm and bearing depth, ie depth of bearing pocket to back of circlip.

[andys]

Wilhelm,

Just catching up after 5 days in Puerto Vallarta, Mexico, thus the late post.

Nice work. Good to see someone thinking outside-the-box. I curious why you chose the 928 bearing? Most think the 914 bearing is more than adequate, and the 911 bearing beyond most needs.

I went with the 911 bearing mostly because it matched the late 911 axles, and I also moved the bearing further outboard in order to fit my 6 speed transaxle. Much like your work, here are a couple of photos of what I did (BTW, I can appreciate the amount of work that goes into this kind of thing). I fabricated a custom trailing arm.

Andys

[Brett W]

One thing to keep in mind, on a unit bearing like these, the distance between the centerline of the wheel and the bearing centerline determines the amount of torque the bearing sees. So you wouldn't necessarily have an overloaded bearing if the bearing centerline and the wheel centerline lined up.

Good job on the parts though. You need to use a little more filler rod and a little less heat on your TIG welds. Looks like you have a little undercutting.

[ClayPerrine]

Wilhelm,

Just catching up after 5 days in Puerto Vallarta, Mexico, thus the late post.

Nice work. Good to see someone thinking outside-the-box. I curious why you chose the 928 bearing? Most think the 914 bearing is more than adequate, and the 911 bearing beyond most needs.

I went with the 911 bearing mostly because it matched the late 911 axles, and I also moved the bearing further outboard in order to fit my 6 speed transaxle. Much like your work, here are a couple of photos of what I did (BTW, I can appreciate the amount of work that goes into this kind of thing). I fabricated a custom trailing arm.

Andys

From experience...


Junk the Wilwood spot caliper. If you set the brake when the rotor is hot, after it cools it won't release. You will end up beating the shit out of the caliper trying to get the park brake off.

[andys]

Clay,

I've read that opinion before, but unfortunately only after I had already completed the work. Do you know why it doesn't release? Is it a symptom of the Wilwood design? Many cars use calipers and pads for parking brake applications, so I'm wondering what's the deal? Guess I'll find out for myself as soon as I get the wheels on the ground. I have all the 911 stuff just in case this doesn't work out.

Andys

[Brett W]

The Carrera GT used a spot type caliper.
(IMG:http://i324.photobucket.com/albums/k329/Machinepro9/DSCN0157.jpg)

[McMark]

Beautiful... (IMG:style_emoticons/default/drooley.gif)

[PeeGreen 914]

Ummm... Can I have that rear suspension? (IMG:style_emoticons/default/biggrin.gif)

[Wilhelm]

"I curious why you chose the 928 bearing? Most think the 914 bearing is more than adequate, and the 911 bearing beyond most needs."

I have a 928 and am familiar with this so had a reference for it during the design phase. Also I got complete rear hubs/carriers/brakes shoe setup for both rear corners of ebay for $25.00 a pop, much cheaper than I saw for any 911 stuff. Like many of you I am a CSOB.

"You need to use a little more filler rod and a little less heat on your TIG welds. Looks like you have a little undercutting."

Thanks, I appreciate any tips. I'm early on in my TIG welding having done MIG for 25 years. While welding this I think I was concentrating more on good penetration and was trying to avoid melting filler onto my weld rather than integrating it into my weld. I can see that it requires more eye hand coordination than MIG. I find myself pausing, taking a deep breathe, and getting set, before running each bead. Seems like with MIG I've gotten used to hitting the trigger and running with it!

[ClayPerrine]

Clay,

I've read that opinion before, but unfortunately only after I had already completed the work. Do you know why it doesn't release? Is it a symptom of the Wilwood design? Many cars use calipers and pads for parking brake applications, so I'm wondering what's the deal? Guess I'll find out for myself as soon as I get the wheels on the ground. I have all the 911 stuff just in case this doesn't work out.

Andys

It is the Wilwood caliper design. for some reason it won't release after the brake cools if it is set when the rotor is hot.

Wilwood discontinued the spot caliper for that reason (that's what I was told when I phoned them about it).



But this is cool..

Hydraulic Caliper with Mechanical Park Brake

Maybe as a replacement for a stock 914 rear?

[ClayPerrine]

The Carrera GT used a spot type caliper.
(IMG:http://i324.photobucket.com/albums/k329/Machinepro9/DSCN0157.jpg)

Custom built brembo caliper, not the Wilwood one. This is a known problem with the Wilwood spot caliper.

[andys]

"I curious why you chose the 928 bearing? Most think the 914 bearing is more than adequate, and the 911 bearing beyond most needs."

I have a 928 and am familiar with this so had a reference for it during the design phase. Also I got complete rear hubs/carriers/brakes shoe setup for both rear corners of ebay for $25.00 a pop, much cheaper than I saw for any 911 stuff. Like many of you I am a CSOB.

"You need to use a little more filler rod and a little less heat on your TIG welds. Looks like you have a little undercutting."

Thanks, I appreciate any tips. I'm early on in my TIG welding having done MIG for 25 years. While welding this I think I was concentrating more on good penetration and was trying to avoid melting filler onto my weld rather than integrating it into my weld. I can see that it requires more eye hand coordination than MIG. I find myself pausing, taking a deep breathe, and getting set, before running each bead. Seems like with MIG I've gotten used to hitting the trigger and running with it!

$25 bux is way cheap; I see your motivation.

Going from MIG to TIG, just slow down a bit and get used to using the pedal to control your heat. As they say, practice, etc.

Andys

[ClayPerrine]

For what its worth, even Wilwood is using a parkbrake like a 911....


Wilwood rear brake kit.

[Brett W]

Glad I haven't bought the Wilwood spot caliper.

[seanery]

nice project! it's very cool!!!

[andys]

Clay,

I've read that opinion before, but unfortunately only after I had already completed the work. Do you know why it doesn't release? Is it a symptom of the Wilwood design? Many cars use calipers and pads for parking brake applications, so I'm wondering what's the deal? Guess I'll find out for myself as soon as I get the wheels on the ground. I have all the 911 stuff just in case this doesn't work out.

Andys

It is the Wilwood caliper design. for some reason it won't release after the brake cools if it is set when the rotor is hot.

Wilwood discontinued the spot caliper for that reason (that's what I was told when I phoned them about it).

Clay/Brett/et al,

Today I phoned Wilwood with regard to Clays experience of the caliper sticking closed after applied to a hot rotor and subsequently cooled. I asked to speak to a tech guy with several years experience. The tech guy told me he is unaware that any problems exist in this regard. The only complaints they have center around the un-fixed pad rattling (the moveable pad simply sits loosely in a cavity and can rattle around; kind of a poor design, IMO). He said many of these spot calipers are used on kit cars without issue. BTW, they still offer the spot caliper anlong with replacement pads even though it is not listed on the current site (?). Nevertheless, I told him if I encounter a problem like Clay described, I will call in the complaint. He welcomed any feedback without apprehension.

So, I will try out the spot caliper as you see it in my photo. If it sticks as, Clay describes, I'll post it here and call Wilwood. In the meantime, I'll keep my Carrera parking brake hardware just in case.

Andys

[charliew]

I don't know why this additional challenge occured to me yesterday but I really appreciate you'all sharing your solutions as they are great.

I wonder if the wilwood caliper or the pads are already heated up and have expanded more than the rotor when the brake is set and therefore the pads are bound up from the rotor not shrinking as much as the caliper? If it does happen and you do get it loose you might try a cushion spacer of some type under the stationary pad to keep it from being bound up on cooling, maybe even a warped washer ( I don't remember their real name)

It could also be the flexing of the mounting bracket from the leverage applied to the arm. I am sure you can figgure it out and make them work.

I know it's a pain but if it does lock up you might try jacking up the car and loosening the wheel and rotor and it might save beating the caliper up.

Both solutions look great to me.

I am going to try to move the 914 bearing housing out ward andrefabing the arm or a copy of the arm out to it to try and not have the stub axle so far up in the bearing housing, this may prove to be easier said than done. I currently think the 914 bearings are large enough. I already have the 911 brake and stub stuff and it looks to be enough brake for a hot suby in this light car to me.

I think it's better to have more heat than filler than more filler than heat.
My previous experience with torch welding helped me on my curve with tig. I don't have any grip in my left hand so I have to stop and reposition the wire pretty often so that is my challenge. My best friend is a welder and fabber by trade so I have all the advice I will ever need. His beads are almost robot perfect.

I guess my search abilities are not real good as I missed this yesterday when I was starting this solution search.