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Old 06-22-2023, 02:39 PM   #1
robkay
 
Drives: Hatch
Join Date: May 2009
Location: NW OH
Posts: 89
Question about KYB rear shocks

I just found that one of my OEM rear shocks is dripping a little oil (154,000 miles). I see that the current KYB replacement is 343442 Excel-G.

So, on the KYB website it recommends SM5858 mounting kit.

Has anyone who installed KYB's used the mounting kit, too?

Just trying to figure out whether I need it. THX
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Old 06-22-2023, 04:25 PM   #2
sh0rtlife
 
Drives: 2007 5dr canadian import
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Posts: 1,025
generaly speaking the mounting kits are nothing more than replacement nuts and bushings which generaly come with the shocks
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Old 06-23-2023, 10:14 AM   #3
WeeYari
 
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By the looks of things, the shock may not have an included dust cover which appears to be in the "kit".
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Old 10-27-2023, 01:12 PM   #4
robkay
 
Drives: Hatch
Join Date: May 2009
Location: NW OH
Posts: 89
So this is a follow-up which may be helpful to others considering KYB rear shocks. I consulted with KYB Tech Support (email only) throughout the install.

For my '07 hatchback I bought both the KYB shocks (343442) and kits (SM5858).

You do want the kits because it has replacement hardware and cushions. Your OEM hardware on the underside may be rusted to the point of potential compromise. (Mine was very rusty and flaking.) As far as I can tell, the hardware is essentially identical to the OEM parts.

KYB does the dust cover a little different than the OEM, though. As far as I can tell, the OEM was manufactured such that the dust cover is attached to the steel cushion retainer cup. KYB does it differently. They use a large, white rubber "bumper" they call it, which is separate from the steel retainer cup. The dust cover is held in place simply by friction of the rubber to the shock shaft. In the long run, does this work well? I'm a bit skeptical, but we'll see. I kind of felt like maybe I should have applied like some trim adhesive to try to glue the rubber to the metal cup, but I did not. Hopefully the dust cover will stay in place where it is supposed to. We'll see.

Now, here is something YOU REALLY NEED TO BE AWARE OF and that is the connection at the top end of the shock.

The OEM uses a "two (2) nut" system where the lower nut is basically used to apply the proper amount of compression to the rubber cushion and this is accomplished, not by torque spec, but by "vertical measurement" with (per the service manual), 15-18 mm from the top of the (lower) nut to the tip of the threaded shock shaft. Then you use a second nut, a "jam" nut, to hold the lower nut in place and this 2nd nut you "torque" to 18 ft lbs.

KYB simplifies the installation by providing a "lock nut" with the shock and thus there is no need for a 2nd nut (jam nut).

So, based on the OEM spec, you might think you should torque KYB's lock nut to 18 ft. lbs., right? In fact, KYB Tech Support reinforced this spec to me. Well, I was twisting it down and not getting my torque wrench anywhere near clicking. It dawned on me, "Hmm. Somethin' doesn't seem right here."

I looked at the OEM side and decided to take a measurement from the top face of the steel washer (cushion retainer) to the tip of the threaded shock stem and it was 1". Well, I had the KYB side screwed down to almost the same and, as I said above, the torque wrench was no where near clicking. Also the compression of the rubber cushion looked to be about the same as well.

After pondering the situation, it dawned on me, Toyota's 18 ft. lb. spec is not the spec for compression of the rubber cushion. In their "two nut" system, it is the spec to tighten the jam nut against the lower nut (which is why you use two wrenches). Had I kept cranking KYB's lock nut down to 18 ft lbs. I would have had a disaster.

I adjusted the lock nut down to where the distance from the face of the washer to the tip of the shock shaft matched the OEM side (1"). I then consulted again with KYB Support and they said, "You know what...we think you're right on that." Thinking about it further, the OEM nuts are 7mm thick. So, if you take the 15-18mm and add 7mm you get 22-25mm. 25mm = 1" so a 1" measurement is right there.

KYB emphasises that your final torquing/adjusting (top and bottom) should be done with the car back on the ground as the specs are based on having the suspension loaded. Also, with the car on the ground, the weight will ensure that the top of the shock shaft is pushed up vertically as far as possible.

BTW, the "instruction" paperwork that comes with KYB's parts is next to worthless. You're best to refer to Toyota's service manual for the car along with a few Youtube videos to "get educated."

Overall, though, it is an easy job. Everything is easily accessible. Over the previous week I had hit the lower connection with PB Blaster 3-4 times and, although, the connection was rusty, I had little difficulty working the nut and bolt off. I cleaned them up good with Gunk and then brake parts cleaner and used some red thread lock at reinstallation.

As far as ride, at this point I really can't feel any difference between the OEM shock and the KYB.

If anyone has any comments or suggestions on the above I welcome the input.

Last edited by robkay; 11-02-2023 at 03:34 PM.
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Old 11-03-2023, 01:04 PM   #5
Type-Y
 
Drives: 2007 Yaris hatch
Join Date: Jun 2017
Location: NY
Posts: 135
Quote:
Originally Posted by robkay View Post
So this is a follow-up which may be helpful to others considering KYB rear shocks. I consulted with KYB Tech Support (email only) throughout the install.

For my '07 hatchback I bought both the KYB shocks (343442) and kits (SM5858).

You do want the kits because it has replacement hardware and cushions. Your OEM hardware on the underside may be rusted to the point of potential compromise. (Mine was very rusty and flaking.) As far as I can tell, the hardware is essentially identical to the OEM parts.

KYB does the dust cover a little different than the OEM, though. As far as I can tell, the OEM was manufactured such that the dust cover is attached to the steel cushion retainer cup. KYB does it differently. They use a large, white rubber "bumper" they call it, which is separate from the steel retainer cup. The dust cover is held in place simply by friction of the rubber to the shock shaft. In the long run, does this work well? I'm a bit skeptical, but we'll see. I kind of felt like maybe I should have applied like some trim adhesive to try to glue the rubber to the metal cup, but I did not. Hopefully the dust cover will stay in place where it is supposed to. We'll see.

Now, here is something YOU REALLY NEED TO BE AWARE OF and that is the connection at the top end of the shock.

The OEM uses a "two (2) nut" system where the lower nut is basically used to apply the proper amount of compression to the rubber cushion and this is accomplished, not by torque spec, but by "vertical measurement" with (per the service manual), 15-18 mm from the top of the (lower) nut to the tip of the threaded shock shaft. Then you use a second nut, a "jam" nut, to hold the lower nut in place and this 2nd nut you "torque" to 18 ft lbs.

KYB simplifies the installation by providing a "lock nut" with the shock and thus there is no need for a 2nd nut (jam nut).

So, based on the OEM spec, you might think you should torque KYB's lock nut to 18 ft. lbs., right? In fact, KYB Tech Support reinforced this spec to me. Well, I was twisting it down and not getting my torque wrench anywhere near clicking. It dawned on me, "Hmm. Somethin' doesn't seem right here."

I looked at the OEM side and decided to take a measurement from the top face of the steel washer (cushion retainer) to the tip of the threaded shock stem and it was 1". Well, I had the KYB side screwed down to almost the same and, as I said above, the torque wrench was no where near clicking. Also the compression of the rubber cushion looked to be about the same as well.

After pondering the situation, it dawned on me, Toyota's 18 ft. lb. spec is not the spec for compression of the rubber cushion. In their "two nut" system, it is the spec to tighten the jam nut against the lower nut (which is why you use two wrenches). Had I kept cranking KYB's lock nut down to 18 ft lbs. I would have had a disaster.

I adjusted the lock nut down to where the distance from the face of the washer to the tip of the shock shaft matched the OEM side (1"). I then consulted again with KYB Support and they said, "You know what...we think you're right on that." Thinking about it further, the OEM nuts are 7mm thick. So, if you take the 15-18mm and add 7mm you get 22-25mm. 25mm = 1" so a 1" measurement is right there.

KYB emphasises that your final torquing/adjusting (top and bottom) should be done with the car back on the ground as the specs are based on having the suspension loaded. Also, with the car on the ground, the weight will ensure that the top of the shock shaft is pushed up vertically as far as possible.

BTW, the "instruction" paperwork that comes with KYB's parts is next to worthless. You're best to refer to Toyota's service manual for the car along with a few Youtube videos to "get educated."

Overall, though, it is an easy job. Everything is easily accessible. Over the previous week I had hit the lower connection with PB Blaster 3-4 times and, although, the connection was rusty, I had little difficulty working the nut and bolt off. I cleaned them up good with Gunk and then brake parts cleaner and used some red thread lock at reinstallation.

As far as ride, at this point I really can't feel any difference between the OEM shock and the KYB.

If anyone has any comments or suggestions on the above I welcome the input.
Thanks for the useful follow up. I am currently running Tein coilovers, but was thinking about switching back to stock struts and rear shocks/springs for the winter, but then found the KYB quick struts that come pre-assembled and thought these may be a good alternative to having my original struts put back together (Tein uses the original top hats) and then having to repeat the process when I go back to the Teins. Though I wonder about how they compare to stock.
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Old 06-05-2024, 07:41 PM   #6
soldiersvejk
 
Drives: 2009 Toyota Yaris Sedan
Join Date: Jun 2017
Location: Massachusetts
Posts: 12
Thank you. A service manual is really indispensable.
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