Rebuilding a CAS

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Rebuilding a CAS

Post by n12sumfin » Sun Jan 09, 2011 10:38 pm

Okay since i had the fun job of rebuilding this i thought i would share my experiences :) Sorry i dont have pics of everything but you should be able to have a go with what i have written :)

You will need:
1x CAS unit cost about $165 or so from petroject or your local efi spares (there is 3 different types, 1 has internal threading in the cas unit and is held in by screws in the bottom, the others are held in by screws from the top of the cas unit)

1x 12x22x7 single v-groove Nitrile rubber seal

1x 6200 zz Bearing

soft faced hammer
screw drivers and sockets
Oring picks or similar
other useful tools

here is 2 pics of the failed cas units 1 had a seized shaft, failed bearing and stuffed cas


other had a failed oil seal and was contaminated with oil



** Take note of where the washers sit in the dis-assembly process as i spaced out everything according to my discretion**

take your old dizzy out of the car

remove the 2 screws on the base and take out the plug

remove the 2 screws on the top and take off the cap

remove the center bolt out of the rotor button and pry off the end of the shaft extension piece

remove 2 small bolts on the side of the dizzy and gently price the brass plate upwards and out of the way


remove a small machine screw on the inside of the shaft extension and pull off the end

DO NOT ATTEMPT TO REMOVE THE 2 SCREWS on the top of the cas at the side it is a sealed unit and will just break!!!!!!!!!!!!!

this happens

next you will have to remove the chopper disc off the end of the shaft, i used 2 screw drivers on both sides through the plate holes to gently wedge it off without damaging it, remember to take note of the top side

remove the locating plate washer again with 2 screw drivers gently

there should be another locating piece on the shaft again with 2 screwdrivers (pain in the ass)

remove the 3 screws out the base of the cas unit

lift out of the way

remove the 2 screws holding the bearing in

turn it upside down and using a soft headed hammer or mallet, tap the shaft down into the housing and it will be able to be pulled through from the other side

now you should have 2 pieces put the shaft down and work on the housing, remove the seal out of the housing (i used o-ring picks and levered it out was a shit of a job) very gently careful not to scratch where it sits otherwise it wont seal properly or seat

and placing the shaft upside down in the vice, sit the bearing so its resting on that and without putting pressure on the shaft, tap the top shaft of the bearing.

YAY first part done

Putting it back together

lightly grease the shaft up and seat the bearing on the shaft


squeeze the new seal into position in the bottom of the dizzy housing and seat home with the help of a small socket and extension if you have one handy the right size


place the shaft back into the housing from the top down until the bearing sits nicely

fasten back into place with the 2 screws


sit the new cas unit in place and fasten with the 3 screws


tap the locating seat back into position

place the washer and locating ring thing back on the shaft


place the chopper wheel very gently back into position sliding it into the slit of the unit and locate on the shaft

fit the top brass locating ring back into position and secure with the screw on the inside of the shaft

Editors Note:
After assembly, CAREFULLY check that the timing wheel is not touching the optical head.
Turn the shaft by hand and listen for any rubbing/grinding noises.
If the CAS has to be lowered, remove the CAS and gently file down the 3 brass screw thread bosses EQUALLY.
To raise it, youll have to work out how far it needs to come up and make some shims out of good gasket paper.
tension everything down again and recheck.


attach the brass plate back on and tighten the 2 screws on the side

put the rotor button back on tighten the small bolt

put the seal back on and replace cap and tighten

Fit a new oring on the bottom


AND your done :)

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Post by Kimmo » Sun Jan 09, 2011 11:12 pm

Onya : )


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