Hi everyone, so I have been trying to locate a new tensioner spring/assembly for some time and have not been able to find one. Does anyone know if there is an updated part or different tensioner or if I could even buy the spring (the part that broke) separately? I've attached what the original part looks like. The ACDelco part number is 12596250 but the issue is everywhere I look the part is either out of stock or on backorder with no estimated in stock availability.
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xapo
There are several failure vectors
-The spring loses tension so the tensioner doesn't push on the belt as hard
-I've seen pictures of one of these tensioners with the metal spring ends/mounts broken.
-And obviously the bearing in the pulley.
The spring is the really nasty part to deal with. It could be completely custom.
You need the original loose length & diameter of an undamaged unused spring, whether the ends are machined flat, and the diameter of the springsteel they coiled it out of.
The LS4 tensioner spring mount pieces can be machined out of aluminum or steel on a mill and maybe a lathe.
The Idler can be sourced or the bearing itself can be replaced.
Samcrac recently discovered that the failed serpentine belt tensioner for the LT5 in his flooded C4 Corvette is discontinued. He was able to cannibalize a different tensioner for the spring and the idler pulley. Sam can be pretty ham handed and his ham handed impatience broke the casting for the lt5 tensioner. I question whether his solution of getting the broken casting welded is going to work long term. I find it entertaining in a cringy way to see what he's going to screw up next.
If you're going to rework one of these tensioners might I suggest exercising patience and care. If being careful and being patient is not your bag you'd do well to find somebody who's cultivated those skills.
-The spring loses tension so the tensioner doesn't push on the belt as hard
-I've seen pictures of one of these tensioners with the metal spring ends/mounts broken.
-And obviously the bearing in the pulley.
The spring is the really nasty part to deal with. It could be completely custom.
You need the original loose length & diameter of an undamaged unused spring, whether the ends are machined flat, and the diameter of the springsteel they coiled it out of.
The LS4 tensioner spring mount pieces can be machined out of aluminum or steel on a mill and maybe a lathe.
The Idler can be sourced or the bearing itself can be replaced.
Samcrac recently discovered that the failed serpentine belt tensioner for the LT5 in his flooded C4 Corvette is discontinued. He was able to cannibalize a different tensioner for the spring and the idler pulley. Sam can be pretty ham handed and his ham handed impatience broke the casting for the lt5 tensioner. I question whether his solution of getting the broken casting welded is going to work long term. I find it entertaining in a cringy way to see what he's going to screw up next.
If you're going to rework one of these tensioners might I suggest exercising patience and care. If being careful and being patient is not your bag you'd do well to find somebody who's cultivated those skills.
I did some Google searches this one has some promise. There's some belt tensioner springs that look similar.
coil spring belt tensioner - Google Search
I own one of these little monsters so I kind of have some skin in the game. It'd be darn nice to be able to find a replacement for the spring.
coil spring belt tensioner - Google Search
I own one of these little monsters so I kind of have some skin in the game. It'd be darn nice to be able to find a replacement for the spring.
You mean stuck?
I'd try removing the tensioner and soaking it in oil then tapping on the spring. Don't beat heck out of it.
At this point I'd be sorely tempted to take it off and take a look at how difficult it would be to take it apart.
You may be able to put a spring compressor on the spring and disassemble it to clean and treat. I think I'd use an oxide treatment like blue or parkerizing on the steel parts or something similar. If you have a place that will yellow zinc plate the steel that would probably last longer. Unfortunately you can't get them cadmium plated. Cad is really quite corrosion resistant.
You may be able to put a spring compressor on the spring and disassemble it to clean and treat. I think I'd use an oxide treatment like blue or parkerizing on the steel parts or something similar. If you have a place that will yellow zinc plate the steel that would probably last longer. Unfortunately you can't get them cadmium plated. Cad is really quite corrosion resistant.
Thanks!!
LS4 Belt Tensioner Kit
Recognizing that this is a real problem for the community, LS4 King has developed a bolt-on solution. We are proud to present the LS4 Belt Tensioner Kit. Each kit comes complete with a self contained spring loaded tensioner assembly, steel idler pulley, mounting hardware and a new serpentine...
ls4king.myshopify.com
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