Hot Rods Chevy 6 lug discs and original wheels

So I am having trouble using my original wheels with a 6 lug disc brake on my 38 Chevy straight axle car. It seems its hard to find a disc that does not push the wheel out (or at least not very far) that I can use my original wheels with. Somewhere I thought I saw someone use a kit that with minor modification of the caliper they ran their OE wheels and it didnt push the wheel out

Right now I have a 6 lug disc from ABS Power Brakes Inc. The OE wheel works but it pushes the wheels out 1-1/16" peer side and the wheel rubs on the fender. I cant do that. From all my research it appears there are only a few manufacturers of 6 lug discs for straight axles. Almost all say that you cant run original wheels. Some say 16s should clear. Some say artilleries should clear.

So, who has run OE wheels with dropped straight axle and discs that didnt shove the wheel out? What disc did you use?

 

Did you change the spindles when converting to disc? If you did, that is probably where your issue is on pushing the wheels out and no disc will fix the issue. Most aftermarket conversion spindles push the width. Only thing you could look at is 63-70 C10 6 lug discs in conversion kits and see if they are narrower. As far as the wheel itself, I think you’re kinda stuck as the backspace is the issue.

 

nope original axle and spindles.

 

Is there a narrower dropped axle available?

 

I did a 1946 Chevy pickup using 1992 Toyota Land Cruiser rotors and calipers about 15 years ago using the stock Chevy hubs with new tapered roller bearings. It moved the wheel out less than 1/4" There was some minor machine work involved on the hub, and longer studs were needed.

 

I’ve seen the original drum hub used for a hat style rotor
Then a fabricated bracket for the caliper
Doesn’t really increase the track width

 

What caliper bracket did you use? Do you have any pictures?

 

thats half the problem Getting the wheels on is the other half

 

Run the drums

 

so what I did on my 39 gmc pickup was use the original hub with the drum removed , then slid a 76-79[?] k blazer rotor over it. the lug studs needed to be changed to longer ones. I made a pattern of the original backing plate bolt pattern , then transferred the holes to the k blazer front backing plate/caliper bracket. the blazer used 6 bolts the straight axle uses 4 . and if I remember right [I did this in 1991] the lower holes needed to have 3/8 spacers between the caliper bracket and spindle. over 120k miles, I am on my second set of rotors and 5 set of pads.

 

WOW!!! Cool. Where did you get the backing plate/caliper bracket? Was it part of the Blazer? And then you trimmed it to fit and used spacers?

 

yes, back then you couldn't swing a dead cat without hitting square body parts. I had a spare 39 front axle, and I took the parts off a parts blazer I had. I set the axle up on the work bench after work one Friday and developed the conversion. the caliper bracket I used happen to be from the only year that used a full steel dust shield bracket. [a square body expert could identify what year] but the bracket with the sheet metal dust shield would work fine.
I had previously installed a dual master cylinder. the next morning I swopped all the stuff over to my truck and drove it out before lunch with working disc brakes.

 

Check out Chevy Astro Van front rotors. They were 6 lug and may be able to make caliper bracket to use front calipers also.

 

I've also seen Toyota discs and calipers employed, just needed the Chevy drum brake hub OD machined down a bit for the rotor to slide over.

 

The ABS unit has a 1 piece rotor and most of the other kits have a hat style rotor for either the stock hub or and aftermarket hub correct ?. You're also talking about the total track width being widened by 2 1/8" (1 1/16" each side) and the stock 16" wheel won't fit.

Are you talking about the stock wheel hitting the caliper or caliper bracket OR just that it's now rubbing the fender lip?

 

Yes the ABS unit I have is a 1 piece rotor. And yes the total track width widened by 2-1/8" and yes the stock wheel just rubs on the fender lip. There is a ton of clearance to the inside.

 

Back in the early 70's we just used a thin (just thick enough) disk brake spacer and took a grinder to the corners of the caliper where it was hitting the wheel when we put a drum brake wheel on a disk brake car and that happened pretty often when guys kept thei custom wheels when they traded cars. You most likely will have to change the studs for longer studs but that isn't a big deal.

Don't even think about driving it this way but stack a couple of same thickness flat washers on each stud and test fit the wheel to see where your miss is as good as a mile point is. Then buy spacers that thickness and they will probably be around 1/4 inch if that. Most local parts houses still show the spacers in thier catalogs or you can get them online. The Transdapt number should be good locally.

I had to use 5 lug but used 5 lug disk brake spacers with the 14 inch Crager Mach 8 wheels that I ran on the front of my 48 for a number of years on the 54 Car front drums.

 

I'll looks but that has been a long time ago. I fabricated the brackets out of steel plate. CAD(cardboard aided design). Likely one bracket to fit the spindle, and a second to fit the caliper and then welded together

 

Well, it didnt work with what I bought so I decided to fix it. I took @tb33anda3rd advice and @Fomocokid for all the fabrication and started buying parts and taking the old hubs apart. I'll post as I get further along. So far, here is where I am: rotors and calipers I used and a trip to the boneyard to get backing plates/caliper mounts. It surprised me how heavy the caliper mounts were. I marked them as a first reference to where they should be mounted (sort of). @Fomocokid fine tuned it to where they should be. This isnt going to look like disc with the full backing plate which is what I wanted

 

rotors and calipers from NAPA - everything is off 72-86 half ton 6 lug 4WD

 

I was looking at the ABS kit also, good to know it kinda*****s. I wanted to use a regular GM rotor (not a hat style) so I could use standard tapered bearings, instead of the Made in China only available in aftermarket bearings.

Great thread and post lots of pics.

 

with that big a year range, the parts support should be readily available for years to come.

 

Thank you for the comment and thanks for the post. Ill show the bearings and at the very end how it differs from the ABS kit. I think the ABS kit is good. They just lied to me when they told me it wouldn't interfere with clearances anywhere with my dropped axle. And then they wouldn't make it right. And their customer support*****s. When Im all done Im going to sell their kit too someone who can use it. Ill post every day or so as I make progress. Should be done soon

 

OK so here is where we are today. I took the hubs and drums to @Fomocokid to press out the wheel studs and separate the drum from the hub. Then he took the races out an put new ones in for tapered bearings and put new longer studs through the rotor and into the hub. When the studs pressed in, he called me and said the studs were not threaded far enough down the shaft to get the wheel flush against the hub. here is a pic. He wondered if it needed a spacer. So I radioed @tb33anda3rd He said keep going it will work without a spacer. So @Fomocokid pressed the studs out and threaded them further down the shaft and re-installed them. They got pressed in and bingo - the wheel goes flush against the hub now. Here are some pics





check this out - you can see the threads arent far enough down the stud


so he threaded them further

 

So when the hub got installed into the wheel this is what it looked like. The wheel is flush but there is no room for a caliper. So I radioed @tb33anda3rd again. he said "keep going, its gonna work" I hope he is right







Ill post more as I go

 

I looked back into the post and didn't see what size wheel you're running (15" or 16"). What bearings did you use?. I have the tapered bearing "kit" that most of the aftermarket companies sell, the bearing don't cross over to anything Timken has (or anyone else). Also what is the wheel stud numbers, it looks like the studs hold the rotor and hub together.

 

I am running OEM 1938 Chevy 16" stock wheels. I think I mentioned it in the very first post. The problem with the ABS Power Brakes 6 lug discs is that they push the wheel out too far. I told them I had a dropped axle before I bougth the kit and they said it wouldnt cause any problems. Well when i measured it they were pushed out 1-1/16" per side. Their kit clears the wheels by a mile but thats all.

As far as the bearings I deal with Chevs of the 40s mostly. They were out of stock on the tapered bearings but ran a set down from the Filling Station. It is part number FS-178K listed as 1923-40 Front wheel tapered bearing kit. I do not have Chevs of the 40s part number.

Yes the stud holds the rotor and the hub together. I got the studs at NAPA. The counter dude is great. He just went in the back and a few minutes later he said this is what they had. NAPA part number 641-1088 listed as "Wheel Bolt"

Shit I hope this works

 

Yup, didn't look hard enough.....you even said 16s. Those look like the same bearings I have. Thanks for the stud numbers, hope it works well also. Sounds like something I might be doing if I want to tow with the panel truck.

I've been into the ABS building when they first opened...not super helpful or friendly.