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Originally Posted by bbundy
(Post 759815)
The thing is if the welds break in this instance it goes back to behaving just like the stock piece in terms of strength and all the steering load goes through the slender flexible shaft through the center that remains free of the heat affected zone from the weld pretty much even if you badly barbeque the outer cage as your welding it. This thing is two parts and The skinny center shaft is fixed at one end only by a small round cross pin. By welding it in this way your just fixing the cage around the center shaft so it cant twist as easily between the hard stops on the cage around it.
I have done this mod and I can say the crummy welds don't scare me at all. The most difficult thing about doing this is welding it without it warping. You would have to be dam lucky to get a continuous bead around the thing without it being warped when it cooled. I put a beautiful tig weld all around one in small increments and it came out warped as shit luckily I had a spare to try it again. If it warps you get tight and loose spots in the pinion adjustment to the rack and it feels horrible. The small dabs at 4 locations might be the best way to do it to avoid warping it. Bob I may try a nonwelding solution the next rack I rebuild. Then there is no chance of heat-warping. |
JBweld the shit out of it?
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Originally Posted by Oscar
(Post 759889)
JBweld the shit out of it?
FWIW the shaft between the rack and the firewall has a splined slip joint in it that is not clamped. To take the slop out of the splines they inject plastic material in it. I have found a cracked downpipe in the right spot will melt that plastic out and you will get play in your steering. Bob |
if the JB weld cracks and falls out in the rack, would there be anywhere it could go to mess something up?
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Originally Posted by shlammed
(Post 760214)
if the JB weld cracks and falls out in the rack, would there be anywhere it could go to mess something up?
Seriously, JB won't crumble. It might let go but it won't disintegrate and wreak havoc with anything. If you look into a stock power steering pinion shaft in the area that gets welded, you'll see the splines. The goal is to keep everything aligned while rendering that spline motionless. However it is done. It is not hard to do via welding and likely via compounds and inserts too. And that same spline and the central "twist" core whose motion we are trying to eliminate remain your safety backups. |
The only reason i mentioned crumbling is because of turning forces and the back and forth vibration coming through the shaft. the JB weld in my experiance doesnt like vibrations.
I understand that you would ideally fill the splines with JB weld if thats how you go about it. |
Originally Posted by shlammed
(Post 760231)
The only reason i mentioned crumbling is because of turning forces and the back and forth vibration coming through the shaft. the JB weld in my experiance doesnt like vibrations.
I understand that you would ideally fill the splines with JB weld if thats how you go about it. |
I baked my pinion in the oven @500 degrees before I welded it. I did about half of the total circumference in quarters and then put it back in the oven to 'cool'. After about 5 minutes to normalize the temperature of the material, I did the other half in quarters and put it back in the oven again. I turned off the oven and let it cool slowly for a few hours while I did something else.
I'm sure it is overkill and a waste of time but reducing the temperature delta by ~450 degrees can't hurt. Mine didn't look as good as Abe's but it looked better than the other example earlier in the post and it didn't crack or warp at all. -h |
Originally Posted by mr_hyde
(Post 764503)
I baked my pinion in the oven @500 degrees before I welded it. I did about half of the total circumference in quarters and then put it back in the oven to 'cool'. After about 5 minutes to normalize the temperature of the material, I did the other half in quarters and put it back in the oven again. I turned off the oven and let it cool slowly for a few hours while I did something else.
I'm sure it is overkill and a waste of time but reducing the temperature delta by ~450 degrees can't hurt. Mine didn't look as good as Abe's but it looked better than the other example earlier in the post and it didn't crack or warp at all. -h |
Exactly. Softer = less brittle. I don't think the 500* oven is enough to drastically effect the metallurgy of the pinion but change in temperatures makes welds brittle. This may have made my welds less brittle by starting the subject hotter and making it cool less (and more slowly). It's been great for almost a full season. As noted correctly above, these aren't going to fail catastrophically anyway.
-h |
What about brazing the shaft? It would involve less heat and should fill the splines with material. Its softer so I don't expect flaking.
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Originally Posted by k24madness
(Post 767811)
What about brazing the shaft? It would involve less heat and should fill the splines with material. Its softer so I don't expect flaking.
I have a tone of experience with brazing having worked building custom steel bicycles back in the 80's and early 90's. Brazing is phenomenal for thin wall stuff and I have done testing to show it better than tig welding in certain applications. Not so good for thick hunks of steel. Tig welding with silicon bronze might a good way to keep the heat and distortion effects to a minimum. lower heat and still have a small heat effected zone. Bob |
Did anyone try the loctite or JB solution yet? When I pull my motor I really should explore removing my PS and would like to see what the results have been for these alternative methods.
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Originally Posted by bbundy
(Post 768131)
I have a tone of experience with brazing having worked building custom steel bicycles back in the 80's and early 90's.
Where did you work, Bob? I've had a few custom steel bikes, some with brazed joints...I had a Landshark (John Slawta) road frame that had beautiful brazed joints with a really nice lugged bottom bracket and seat cluster. [/threadjack] |
I just Tig'ed mine a few weeks ago. 3 ribbons about 3/8 long. I didn't check it for warpage but it all went back together fine.
The gap filler loctite (for worn keyways) should work well. |
I spoke to a mate about welding it up today - he didnt really want to do it just "incase" but both him and his manager suggested loctite 680 or 290. Has anyone tried either of these or have thoughts on the matter? I haven't had too much to do with loctite, so i'll have to do a bit of reading before i come to a conclusion.
cheers plohl |
I'm in the process of depowering the rack from my 1997 car. I'm going to give the Loctite 680 a try. If it fails, then I guess I can just clean it up and have it welded like everyone else. If it works in the long-term then it may be a viable option that we can recommend.
Here's a question though: Does anyone know what the actual diametral gap is between the two parts of the pinion shaft? I'm trying to decide whether or not to use the activator. It is recommended if you are near the gap limits for the retaining compound, but indicates that the ultimate strength of the cure will be slightly lower than if cured without activator at closer tolerances. |
Originally Posted by hustler
(Post 758196)
On second thought, the pinion probably won't fatally break, but the welds will and the spline will stay together. It's still a Helen Keller weld and I wouldn't pay a cent for work like that.
I took a 2 sheets of 16ga mild steel and put one tack on them as a butt weld. It took 60 lbs to pull them apart. |
2 Years Later...
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Hey all, I'm in the process of installing power steering back into my Miata to sell. I bought an untouched powered rack and swapped it out with my depowered rack. For those of you just reading, the pictures hustler posted were of the pinion that's in the depowered rack for my car that Karl at ART welded.
I unbolted the pinion yesterday to see how the welds are doing and they look intact. This setup has been in the car for 2 years now with at least 12 track weekends on it. I'm not saying it's bullet proof but it has definitely withstood some forces applied to it. I'm attaching photos I took of the welds and how they look 2 years later... |
Can I haz?
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