Official CAS Disassembly

Discuss the RB20, RB25 and RB26 series engines.
Booztd 3
Posts: 708
Joined: Sat Jan 20, 2007 8:28 am
Car: 1990 Nissan 300ZX TT
Contact:

Post

Guys

This is how you properly disassemble an RB26/RB25/Z32 CAS

The purpose of the disassembly was to install the 24-tooth AEM Disc

This particular write-up will show pictures of a Z32 CAS. The only difference I noticed in taking both RB26 Mitsu and Z32 Mitsu CAS was the 3 screws for the main cover.

Pictured below, begin by removing the 3 screws for the cover. On the Z32, it uses tamper proof screws, the RB just uses regular screws. I used my smallest chisel punch and tapped them until they came loose, and then finished removing them with a large flathead

Image

Once the screws are out, lightly tap the shaft of the CAS, and it will separate from the cover

Image

Next, the dowel pin holding the engagement shaft on to the CAS assembly

Image

I placed the CAS in a small vice where it could not move 'downwards' and used an air hammer with a grinded off punch

Image

Image

You can see I got the dowel to move. I used a small punch to remove it the rest of the way. You may have problems getting the pin out, on the RB CAS, I had to take a die grinder with a cut-off wheel and grind off the flat spot that was holding the dowel in place

Image

Main cover, engagement shaft, dowel pin

Image

Now, the front bearing needs to be removed. I accomplished this by using a small 7mm socket to fit over the 1/2 moon piece that engages the camshaft 1/2 moon. (the CAS below had the indexing key broke off, so i was able to just set the puller right on the intermediate shaft) I then used a small 3 jaw puller purchased from harbor freight for just a few dollars. I had to grind the bottoms off of the jaws so it would fit all the way under the bearing

Image

Here you can see the bearing is removed, next you want to remove the 2 gold screws that hold the intermediate shaft to the main shaft

Image

After removing the 2 small screws, you need to press the main shaft out of the lower bearing. Begin by popping off the rubber Mitsu cover. I used a smaller socket to fit into the bearing and onto the main shaft. Again, I used the small puller to press out the main shaft. I used the small punch to hold the shaft from spinning while I turned the puller

Image

I apologize for the following blurry pic, but after the intermediate shaft is removed, the wheel will come right out. Its held in place by being pressed in between the main shaft and intermediate shaft.

Image

Now install the AEM 24 tooth disc. You can see the disc below. You DO NOT need to remove the actual black part of the sensor. I only did this for educational purposes

Image

Once the disc is in, place the intermediate shaft back onto the main shaft and secure the 2 small gold screws. At this point the main shaft needs to be pressed back into the lower bearing. I accomplished this by placing the front bearing back over the intermediate shaft, and then using a socket, and a vice as a press. Press the bearing on until it seats, and it will continue to press the main shaft into the lower bearing.

Image

After that, you need to install the engagement shaft and the dowel pin. Once again I used the bench vise

Image

Now install main cover and 3 securing screws, as well as the rubber dust cover on the back side. The CAS should spin freely. If not, you dont have the shafts and bearings seated properly.

Image

Image

I had a used leftover Z32 harness that I cut the connector off of, and depinned the RB CAS connector, and then pinned it back into the Z32 connector. Installed on the car, and here is the result

Image

Dont forget to make the necessary software changes that AEM requires

http://forum.aempower.com/forum/index.p ... ttach=6108

The car started right up, and after getting some seat time, the typical 'hiccup' stock CAS sensors have is now gone. The car accels significantly smoother, and I went out and did some 25psi pulls and didnt have a single issue. Hopefully hitting the dyno up friday!

Cheers!


240z4u
Posts: 2071
Joined: Mon Feb 21, 2005 4:47 am
Car: '95 Nissan 240SX

Post

Your pictures are 100x better indeed.

Looks good man. Thanks for the tutorial.

eh?
Posts: 76
Joined: Thu Apr 22, 2010 10:04 am

Post

An easier method for those who do not have the tools to remove the pin:

Take a needle nose vice grip to remove the two gold screws beneath the bearing. You can then remove the shaft and slip off the wheel. Add a bit of loctite on re-installation for extra security. I did mine like this 3 years ago with no problems.

User avatar
stevespeed
Posts: 671
Joined: Fri Jun 24, 2005 7:07 pm
Car: RB-Swapped S13, FTW
Contact:

Post

Awesome write up dude! After reading this I am gona give another look to going AEM instead of Wolf3D

xJLCx
Posts: 1
Joined: Sun Sep 11, 2016 5:05 pm

Post

Reviving old thread, the images aren't working. Very good write up, but I am more of a visual learner.
thank you

Yellow4g63
Posts: 3718
Joined: Mon Jan 20, 2003 6:07 pm
Car: 95 RB20 240, 91 NX2000 VE power, 95 Stock 240sx
Contact:

Post

I did it for my AEM disc install and it was a HUGE pain in the a**.

RRRRB
Posts: 758
Joined: Wed Jun 01, 2011 9:31 am
Car: 98 RB powered S14
Location: WA

Post

Ive done the AEM disc as well, its not hard once you have done it a coupe times.. initially its a PITA, but Kudos to OP the guide is Helpful


Return to “RB20DET / RB25DET / RB26DETT Forum”