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Can I weld a tab on my front spindles?

13K views 15 replies 8 participants last post by  Quarter Flash 
#1 ·
Can I weld a tab on my front spindles? I am working on an 80 Monza Drag Car. I ordered an Aerospace front brake kit for my car. In the kit it requires me to weld a tab on to the spindle to support the caliper bracket. The kit is excellent quality, but requires some fabrication skills to center the calipers and square the caliper bracket with the spindle shaft. I hesitate to weld this tab on to my spindle because it appears to be cast iron. There is another spot I could drill and tap a hole in the spindle but then I would need to weld a 3\4" tab on to the aluminum caliper bracket. I think it is safer to weld the aluminum than the cast iron. The spot I need to weld the tab onto the spindle is three inches from the spindle shaft location. Can I mig weld cast and if so what is the process. I have a Hobart 220 volt 175 amp mig welder and I am a pretty fair mild steel welder.

Bob
 
#2 ·
Spindle material

Quarter,
I doubt the spindle is made of cast iron. More likely it is forged steel. Check with supplier to be sure. If you are not sure, don't take a chance with brakes. Go to a shop with experience and see if they will work with you or do the job for you if their insurance will not permit them to help you do it.
 
#5 ·
If it was me I would not MIG weld it.
I would do a little pre heat and TIG weld it just to make sure that the weld would not crack.

If someone brought me a spindle and kit with a weldable tab I'd contact the company who made the kit and ask them send me thier recomendations for welding in writing.


I'll bet oldred would know a more specific welding procedure once you find out exactly what materials you are welding together. Is the tab CRS or hot rolled?

Later, mikey
 
#6 ·
Hi Bob - most spindles are forged from highly weldable, malable material. I've built a few 49-54 GM 3" drop spindle supports, made from similar stuff, and never had a problem with 'em coming apart. The kit you've got must be adapting 11" rotors and bigger calipers to your existing spindles.
If it was me doing the welding, I don't think I'd use hardwire MIG. I'd probably go with a Certainium alloy rod and try to get the area to be welded preheated a bit, without warming up the shaft too much then I'd peen the hell out of the weld to relieve it as much as possible.
The guys you bought the kit from probably know the best approach though, I'd check with them to see if they're willing to hang their necks out on your project.
 
#7 ·
Welding Spindles

As always this site is my best friend when it comes to good information. I think I will machine the spindle and put a small pin in the tab and spindle so it will remain in place. Take it to a pro and have it tigged. The tab needs to be fitted with the rest of the kit in place so it will align properly when I bolt it up. I don't want any welding going on near my beautiful new brake parts. Thank you for the help.

Bob
 
#10 ·
Cast or forged????

I don't know for sure. I guess I will take it to a professional welder (with good refs) and show it to him. We have a fabricator in Gresham OR that comes highly recommended as a race car fabricator and welder. That is where my spindles most likely will go. His name is Bill King.

Bob
 
#11 ·
How to tell casting vs forging

This is not true 100% of the time, but a forging usually will have a smoother surface texture on the unmachined surfaces than a casting. You can usually see the texture of the sand used in the mold of a casting. A forging's surface will show irregularities from the hammering but without the texture of sand casting. An experienced fabricator or welder can usually tell with just a visual inspection. The exceptions are usually found on very expensive imported castings and some pre-WWII castings on expensive American machines.
As many have already pointed out, do not get stingy when working on the brakes. If something goes wrong, you can be held liable for any damages, or deaths.
As one of Clint Eastwood's characters said: "A man's gotta know his limitations".
 
#12 ·
1948 thames said:
how do you tell the differance between cast and forged spindles? Is it the same as a crank shaft as in the width of the parting line?

I think Mike answered that question just right. Bob, frankly, If you find the spindles you have are cast, I wouldn't use them on your Monza race car even in virgin form.. A short wheel based car like that, makin' lots of horsepower, is bound to see some air under the front tires. The law of gravity says everything that goes up must come down. That's WAY more stress than I'd ever put on a set of cast iron spindles - welded or not.. :)

With the right rod, even the most porous of iron castings can be successfully welded up stronger than the material being altered or repaired. I went to a trade show several years ago and watched a piece of 6" soil pipe (possibly the lousiest grade of cast on the planet) welded up with Certainium alloy rod. The welded piece was placed in a press and stressed till it broke apart about 3" away from the welded area.
I talked our purchasing agent into springing for 20 pound test pack of the stuff and use it all the time on all sorts of small repair projects that require high integrity welds.. It hasn't let us down yet.
 
#13 ·
Welding Spindles

I did several tests over the weekend. As part of the brake kit I bought I have to remove the ears for the stock brake calipers. This gave me an opportunity to weld the two ears together and put them in my rather large vise and smack them with a ten pound sledge. So I have my leather apron, face shield and leather arm guards on. I put one end of the welded pieces in the vise and give them a little tape at the end of 3 1\2 foot handle and the weld held. Feeling fairly confident that my spindles are forged steel I wonder how good my weld is? I do have a little fear that a piece of metal could fly off and penetrate my leather apron and even worse knock off one of the boys. So I properly shield myself with a couple pieces of scrap metal and some bailing wire. I smack this piece three times hard and it doesn't brake. I am confident it is forged steel and can be tig welded better than I can mig the pieces I hammered. I will post pics of the project as I assemble it.

Bob
 
#14 ·
without seeing your project, it sounds to me like the "ears" you need to weld onto your spindles are more for simply retaining the calipers in the mounts. Sounds like they won't be bearing the actual brunt force of a 125 MPH quick stop.

There's always the parachute and a pair of steel toed boots with a hole in the left side floor pan, just in case... :sweat: :D

If it gets by tech, what the heck.
 
#15 ·
Spindle

The ears I removed from the stock spindle were garbage that was not needed with the new kit. The tab to be welded to the spindle is the forth mounting bolt location. The kit says its optional but that usually means do it in my book. I needed to cut the caliper ears off the stock spindle so the new calipers would clear. These junk pieces of metal are what I welded together for the sledge test. Pics coming when done.

Bob
 
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