Engine, Drivetrain & Forced-Induction
Have Technical Questions or Done Modifications to the G37? Find out the answer in here!

Is there a DIY for Replacing Pulleys?

Thread Tools
 
Search this Thread
 
Old 09-26-2019 | 05:32 PM
  #1  
Joyryde's Avatar
Joyryde
Thread Starter
Banned
iTrader: (1)
 
Joined: Aug 2018
Posts: 481
Likes: 61
From: United States
Is there a DIY for Replacing Pulleys?

Has anyone replaced their whole pulleys system including the tensioner? My pulleys and belts are on their way out soon so I was wanting to know if there’s a DIY anywhere? I couldn’t find any from Google and the Myg37 search bar, only serpentine belt changes. And is there anything else I should know? I heard that there are special pulley tools to check if you don’t tighten it too much so the belt won’t snap.
Old 09-26-2019 | 07:08 PM
  #2  
ILM-NC G37S's Avatar
ILM-NC G37S
Registered Member
iTrader: (3)
 
Joined: Apr 2014
Posts: 4,322
Likes: 1,351
From: NC
Replacing the tensioner (and pulley's) is relatively easy. One bolt for each pulley. The only "special tool" you would need, unless you already have one, is a good quality torque wrench. Very important that you DO NOT OVERTIGHTEN the bolts. The entire procedure as outlined in the FSM (no mention of a "special tool"):


I circled the bolt torque specifications in blue and are measured in ft.-lbs.

Hope this helps!
The following 2 users liked this post by ILM-NC G37S:
Baadnewsburr (09-27-2019), Joyryde (09-27-2019)
Old 09-27-2019 | 12:49 AM
  #3  
Joyryde's Avatar
Joyryde
Thread Starter
Banned
iTrader: (1)
 
Joined: Aug 2018
Posts: 481
Likes: 61
From: United States
Thank you! How do you know if it is too tight or too loose? Sorry if I sound like a novice, I just never done anything with the pulleys besides changing the serpentine belt.
Old 09-27-2019 | 01:36 AM
  #4  
codeflux's Avatar
codeflux
Registered Member
iTrader: (12)
 
Joined: May 2004
Posts: 241
Likes: 29
From: San Francisco, CA
Originally Posted by Joyryde
Thank you! How do you know if it is too tight or too loose? Sorry if I sound like a novice, I just never done anything with the pulleys besides changing the serpentine belt.
You need a torque wrench. Or a mechanic.
Old 09-27-2019 | 10:14 AM
  #5  
Baadnewsburr's Avatar
Baadnewsburr
Super Moderator
iTrader: (3)
 
Joined: Oct 2014
Posts: 1,784
Likes: 320
From: Toronto
Originally Posted by ILM-NC G37S
Replacing the tensioner (and pulley's) is relatively easy. One bolt for each pulley. The only "special tool" you would need, unless you already have one, is a good quality torque wrench. Very important that you DO NOT OVERTIGHTEN the bolts. The entire procedure as outlined in the FSM (no mention of a "special tool"):


I circled the bolt torque specifications in blue and are measured in ft.-lbs.

Hope this helps!
a little curious about this one myself...and I was wondering about special tools for this cause for example I've done the crank pully bolt and A/C clutch on other cars and always ended up needing a holder tool of some sort to get the bolt off and thsoe were on cars with a ton of working room...theres so little working room on the G though so was sure I'd need some special tool to do the tensioner...
Old 09-27-2019 | 11:14 AM
  #6  
ILM-NC G37S's Avatar
ILM-NC G37S
Registered Member
iTrader: (3)
 
Joined: Apr 2014
Posts: 4,322
Likes: 1,351
From: NC
You would only need a "special tool" (something to hold the pulley still) in cases where the bolt is secured to the shaft itself (which turns). If you think about it, the crank pulley, AC compressor, alternator, P/S pump- just about every belt driven accessory- has the bolt (nut in some cases) directly attached to the shaft.

In the case of the idler pulleys the mounting bolts are attached through the pulley bearing directly to the block. Torque values must be followed exactly here: too loose and the pulley bearing can work the bolt free (causing the pulley to fall off) while too tight and you risk cracking the timing chain case. The bolt for the tensioner passes through the spring housing and is not subject to any rotational force.

Maybe this stock image will help you visualize:

Hope this helps...
The following 2 users liked this post by ILM-NC G37S:
Baadnewsburr (09-27-2019), Joyryde (09-27-2019)
Old 09-27-2019 | 01:56 PM
  #7  
Surfnazi's Avatar
Surfnazi
Registered Member
 
Joined: Nov 2013
Posts: 2,110
Likes: 176
Autozone rents pulley puller for free
Old 09-27-2019 | 04:46 PM
  #8  
Baadnewsburr's Avatar
Baadnewsburr
Super Moderator
iTrader: (3)
 
Joined: Oct 2014
Posts: 1,784
Likes: 320
From: Toronto
Originally Posted by ILM-NC G37S
You would only need a "special tool" (something to hold the pulley still) in cases where the bolt is secured to the shaft itself (which turns). If you think about it, the crank pulley, AC compressor, alternator, P/S pump- just about every belt driven accessory- has the bolt (nut in some cases) directly attached to the shaft.

In the case of the idler pulleys the mounting bolts are attached through the pulley bearing directly to the block. Torque values must be followed exactly here: too loose and the pulley bearing can work the bolt free (causing the pulley to fall off) while too tight and you risk cracking the timing chain case. The bolt for the tensioner passes through the spring housing and is not subject to any rotational force.

Maybe this stock image will help you visualize:

Hope this helps...
Thank you. This is exactly the explanation I needed and why this site is so great.
Old 09-28-2019 | 02:05 AM
  #9  
UCLAG37's Avatar
UCLAG37
Registered Member
 
Joined: Aug 2008
Posts: 145
Likes: 22
From: NOVA
I replaced all my pulleys when I replaced the tensioner. As mentioned by others, no special tool is required. Actually it is a very easy job. I used my Gearwrench 3680 Racheting Serpentine Belt tool which made it easy to remove the tensioner. The pass-through sockets of the Serpentine Belt tool can also be used to remove the shock mount on our struts so not a bad investment if you do maintenance and repairs on your own vehicle.

Here is a pic of the pulleys and the tensioner that I replaced on my coupe at 77,000 miles/10 years. The pulley bolts are attached to the pulley.

Good luck!

UCLAg37



The following users liked this post:
Baadnewsburr (09-30-2019)
Old 10-06-2019 | 01:13 AM
  #10  
Str8Gtime's Avatar
Str8Gtime
Registered Member
 
Joined: Sep 2015
Posts: 24
Likes: 5
I need to replace the exact same pulleys - well at least for me: number 4 and 5 idler pulleys (from diagram above) and tensioner. Any chance you can list where you purchased them or the part numbers? I found what I think i need from rock auto but I always like make sure.

Additionally, when I took off the serpentine belt - i spun all the pulleys and noticed that my alternator pulley had a fair amount of resistance to it. It spins but just not "freely." Doesn't make any noise and there is no play but I am thinking that it might be starting to seize? First time changing the belt @ 100k miles so I tried to be careful and thorough about everything.

Also if you don't mind listing the torque specs it would help but i can find that information if you don't remember

-Thanks in advance

Last edited by Str8Gtime; 10-06-2019 at 01:22 AM. Reason: adding
Old 10-06-2019 | 03:00 AM
  #11  
UCLAG37's Avatar
UCLAG37
Registered Member
 
Joined: Aug 2008
Posts: 145
Likes: 22
From: NOVA
Str8Gtime,

I usually buy most of my parts from Discountinfinitiparts.com. A link to the parts is below. I believe you need to buy two of the ribbed idler pulleys (11925-JK20D) and one of the smooth surface idler pulleys (11925-EY00A) if you want to change all of them. The tensioner is 11955-1EA9D.

To confirm the parts numbers, go to the Discountinfinitiparts.com and type in your vin number and click on "maintenance and lubrication." Then click on the :"belts and pulleys" link. You need to check your own vehicle because I don't know if any parts numbers have changed from my 2008 model year.

https://www.discountinfinitiparts.co...ts-and-pulleys

After you get the parts numbers, you might also compare prices on dealers who sell on Ebay. I bought my pulleys,belt and tensioner 4 years ago and I noticed the prices have increased about 20-30 percent.

As for torque specs, see the second post above. ILM-NC G37S was kind to circle the torque specs in blue.

Good luck!

UCLAg37
Old 12-22-2019 | 05:10 PM
  #12  
Miketrujillo429's Avatar
Miketrujillo429
Registered User
 
Joined: Dec 2019
Posts: 1
Likes: 0
BOLT size

Hey guys so my idler pulley completely came off on the freeway when I was driving from Utah to Arizona, luckily I made it to Phoenix but the entire pulley and bolt came off. Anyone know the bolt size I’ll need?
Old 12-27-2019 | 01:35 PM
  #13  
Surfnazi's Avatar
Surfnazi
Registered Member
 
Joined: Nov 2013
Posts: 2,110
Likes: 176
Originally Posted by Miketrujillo429
Hey guys so my idler pulley completely came off on the freeway when I was driving from Utah to Arizona, luckily I made it to Phoenix but the entire pulley and bolt came off. Anyone know the bolt size I’ll need?
which bolt?
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
kkokko
D.I.Y. Installations/Modifications
11
12-11-2012 05:13 PM
Kev@US-Autotech
Supporting Vendors
46
10-13-2010 03:14 PM
C@ciQ
Engine, Drivetrain & Forced-Induction
4
05-06-2009 10:00 AM
NJlakeshoreG
Engine, Drivetrain & Forced-Induction
11
07-03-2008 09:16 AM



Quick Reply: Is there a DIY for Replacing Pulleys?



All times are GMT -4. The time now is 02:36 AM.