Rebuilding the LT5 Belt Tensioner Using Guts from L98 Tensioner

[mgbrv8]

We all know our belt tensioner is rarer than a supermodel at a buffet. The GM/ACDelco part has been discontinued as have all aftermarket variants, including the one by Dayco. I had previously verified with Dayco that the L98 tensioners have the same internals as our LT5 tensioner but Dayco has since discontinued the L98 tensioner as well. You can however find an L98 tensioner in the aftermarket world and you can use the internals to rebuild the one for your LT5. FYI, Dayco still (01/24/25) makes the LT5 pulley, Dayco #89003.

Photos of OEM LT5 Tensioner, GM # 10067479

Available Parts as of 01/24/25:
L98 1988-1991 Belt Tensioner, Zip Corvette # FB-449
L98 1988-1991 Belt Tensioner, Ecklers # EK-25-112206-1
L98 1988-1991 Belt Tensioner, DRIVESTAR 10055897

I wanted to make sure to use basic tools with this rebuild so the average person could do it themselves at home. Please see the graphics I made showing the parts

Disassembly of the L98 unit w/ plastic cover is fairly straightforward:
1) The black plastic cover just pries off with a screwdriver, do so carefully, making sure to distribute force from one side to the other. (as a safety precaution I wired the unit together before prying, unsure of what would happen once the plastic cover was removed; I was pleased to find it wasn't as difficult as I thought and the wire wasn't really necessary).

2) Once the plastic cover is off, remove all the components except for the heavy duty spring and set aside in order. Then, use a chain wrench (or strong strap wrench will work) to take the tension off the spring stop.

3) Once the tension was off the spring stop, I used the wood handle of my hammer and gently tapped the spring assembly back so the stop would not make contact anymore and I could unload the spring tension.

4) Once the spring is unloaded you can remove the spring from the housing; I did this by tapping the exposed part of the spring with a hammer while also putting a screwdriver through the small hole on the backside to tap the spring.

Disassembly of the LT5 unit is only different as the cover is aluminum and tighter:
5) I used a puller with a 1/4 socket (or one a little smaller than the center pin) to press against the center pin. If you use a two jaw puller, make sure the jaws fit in the grooves. (you should be able to rent a puller from an auto parts store or buy a cheap one at Harbor Freight and grind the jaws to fit in the groves).

6) Repeat steps (2), (3), and (4) with the LT5 tensioner

Assembly
7) Replace all of the old, internal components with the new L98 ones but re-use the LT5 aluminum cover.. When you install the new spring, use a large pair of pliers or something of the sort to compress the spring slightly to get it into the housing, it doesn't take much. I also held the spring vertically to keep the Teflon tape from falling out.


David Hetrick (edited by ZBrink for added clarity)

[GOLDCYLON]

Nice project well done


Any thoughts of doing a run of these? Im sure they would sell quick. I would be in for a spare

[mgbrv8]

I don't have any used ones to rebuild, and you cant find them. BTW here is the link to the cheapest Dayco L98 tensioner I could find.

Dave

(01/24/25 - Part has been discontinued; ZBrink)

[-=Jeff=-]

I have a used one I need to rebuild...

[GOLDCYLON]

Im thinking the same I think I have used one as well

[mgbrv8]

Ill tell you what if one of you guys buy the new Dayco and mail me it and you old one I will rebuild it and mail it back for the one that is on you car now. I have a good friend in Japan with a Z that's been down cause of catastrophic failure of his ZR1 tensioner. That way I can rebuild the traded one you give me so I can rebuild it and gift it to him. A perfect brotherhood circle.

Dave

[We Gone]

This is the other option.

http://zr1specialist.com/HAT%20Web/p...0tensioner.htm

[mike100]

Gonna have to try this. I have one with 30k on it that sometimes sticks a little, but isn't completely worn out. I was able to buy one of the last new ones for $199 and was happy to get it at the time.

[mgbrv8]

Wow!!!! $57 bucks. But it will work.

[mgbrv8]

Dynomite Have I mentioned lately that you rock

Originally Posted by mgbrv8

We all know our belt tensioner's are rarer then a supermodel at a buffet. You can't find a new or old one at almost any cost so I started looking into rebuilding mine. I wanted to make sure to use basic tools with it's rebuilt so the average person could do it themselves at home. Our tensioners are made by Dayco. So I called them and got in contact with a wonderful guy named Randy. He verified my thoughts that the L98 tensioners have the same internals as our tensioner. So I ordered a new Dayco tensioner from rock auto with a discount coupon and came out to a total of $38 and it came with the pulley with the belt guides so that was handy because all you can bye right now is the smooth pulley. And I disassembled it first. The disassembly of the new unit with plastic cover is fairly straightforward the black plastic cover on the new one just pyres off with a screwdriver carefully and making sure to distribute force from one side to the other. As a safety precaution I made sure sure to wire the unit together because I wasn't sure what would happen once the plastic cover was removed I was pleased to find that it wasn't as difficult as I thought it would be and really the wire wasn't really necessary but it's a good precautionary measure. Once the plastic cover and the dampener pad and dampener spring was removed and set aside I used a chain wrench to take the tension off the stop. Once the pressure was off I could use the wooded handle of my hammer and gently tap the spring assembly back so the stop would not make contact anymore and I could unload the spring. Once the spring was unloaded all you have to do is remove the spring from the housing I did this by tapping the exposed part of the spring with a hammer and on the other side of the housing is a small hole on the back that I put a screwdriver through to tap the spring. Disassembling the old unit is only slightly different the cover which is plastic on the new one is aluminum on the old one and a litte tighter so I used a puller. I use the small quarter inch socket just a little smaller then the Center pin to press against. If you're going to use a two jaw puller make sure the jaws fit in the grooves you should be able to rent one from an auto parts store or buy one at Harbor freight and grind the jaws to fit in the groves. The rest is just replacing the old or components with the new ones. One note needs to be made though when you install the new spring use a large pair of pliers or something of the sort to compress the spring slightly to get it into the housing doesn't take much and I held the spring vertically to keep the Teflon tape from falling out.

Here is a link to all the photos of the process
https://www.facebook.com/media/set/?...1&l=bb4f436b0a

David Hetrick