Bowden Control Unit Removal from Transmission?

[DerFuror]

27-115 Removing, installing and adjusting control pressure cable with
vacuum actuator depicts a unit that is a very different design than that of the 500E.

What is the proper procedure to remove & install our unit? (I'd rather not sacrifice the part to find out the hard way).

 

[gsxr]

There is a single M6 (10mm hex head) bolt that you loosen above the assembly, which has a rotating metal clamp that holds the control pressure assembly in place. With that clamp rotated upward, the control pressure assembly should wiggle straight up & out (may need to turn slightly to clear stuff - can't remember). The fun part is getting the linkage rod connected properly - tug on the other end to make CERTAIN it's pulling against spring pressure. It's absolutely miserable to attempt an R&R with the trans bolted to the engine, if you bugger it up.

The different designs have either zero, one, or two vacuum chambers. The vac chambers are for the E/S program (not used in USA), or the cold upshift delay (used with catalysts). I think if you buy a new one it has both vac pods and you seal off the E/S port when installing on a USA tranny.

Photos of the 500E trans are here if you need a reference:
http://www.w124performance.com/images/W124_transmission/E500_trans_722.370/

 

[gerryvz]

Photos of the 500E trans are here if you need a reference:
http://www.w124performance.com/images/W124_transmission/E500_trans_722.370/

Show-off !!!

 

[DerFuror]

There is a single M6 (10mm hex head) bolt that you loosen above the assembly, which has a rotating metal clamp that holds the control pressure assembly in place. With that clamp rotated upward, the control pressure assembly should wiggle straight up & out (may need to turn slightly to clear stuff - can't remember).

That's pretty much what I did. When that ("spring-loaded") rod finally popped out & into its hole, I was afraid I broke the black slider it attaches to until I saw its detent hole way up inside the slider cavity (I was expecting to see a different design & started looking around for broken black plastic).

The fun part is getting the linkage rod connected properly - tug on the other end to make CERTAIN it's pulling against spring pressure. It's absolutely miserable to attempt an R&R with the trans bolted to the engine, if you bugger it up.

Yeah, lookin' forward to that. Manual says to have pan removed & go up thru the bottom. Maybe some creativity with a set of offset needle nose pliers can lift the rod from the topside with enough clearance to reach the detent hole without having to go that route...?

I'll find out soon enough when the new oring arrives. The removed oring was very pliable...too squooshy pliable.


PS: There's a white plastic star-adjuster on the box. Mine currently appears frozen. I was thinking it might have had a similar function as the screw mentioned in 27-115. Any significance regarding this item?

 

[gsxr]

Manual says to have pan removed & go up thru the bottom. Maybe some creativity with a set of offset needle nose pliers can lift the rod from the topside with enough clearance to reach the detent hole without having to go that route...?

No need to pull the pan if the trans is on the workbench. The plastic end of the cable has a guide which helps route the metal rod where it belongs. Forget if needle nose pliers are required. If you are doing the job with the trans in the car, then yeah, need to drop the pan.

I'll find out soon enough when the new oring arrives. The removed oring was very pliable...too squooshy pliable.

Hmmmm. Wonder if that was an aftermarket/non-OEM 'ring...

PS: There's a white plastic star-adjuster on the box. Mine currently appears frozen. I was thinking it might have had a similar function as the screw mentioned in 27-115. Any significance regarding this item?

Mine are the same way. It doesn't turn. I'm thinking either it was never designed to rotate, or it's factory set and glued in place?

 

[DerFuror]

Well, I cleaned off the Control Unit for further inspection.



The star wheel does rotate. The top of the star also accepts a 5mm hex socket (allen key) for adjustment (I marked its current setting & didn’t mess with it too much).



27-115 covers 4 & 6 cyl units of different design where a hex socket bolt adjusts distance “a” between front face of control pressure valve & closure plate when testing the assembled unit with a vacuum actuator. The documentation is vague, but it appears the same item is also noted as the control pressure cable lock?

Maybe Klink or Vader can shine a light on this item's true 8 cyl purpose.

Another anomaly from 27-115 is that although an insertion bore exists, it doesn't seem that its corresponding limiting rod (item 111) exists in the 500E tranny (or I can't find mine).

Also, I did figure out how to remove & reinsert the link rod and unit. Once unclamped from the retaining bracket, the unit must be rotated 90 degrees so the green portion is perpendicular to the transmission…then lift the unit up while gently wiggling the unit free from its orifice & the link rod. Reverse the procedure for reinstallation.

 

[gsxr]

Cool! Guess I didn't try hard enough to rotate the star wheel, probably was afraid of breaking something. Would love to know what it does...

 

[nocfn]

Cool! Guess I didn't try hard enough to rotate the star wheel, probably was afraid of breaking something. Would love to know what it does...

Passenger ejection seat sensitivity module.

 

[DerFuror]

What is the proper procedure to remove & install our unit?

Also, I did figure out how to remove & reinsert the link rod and unit. Once unclamped from the retaining bracket, the unit must be rotated 90 degrees so the green portion is perpendicular to the transmission…then lift the unit up while gently wiggling the unit free from its orifice & the link rod. Reverse the procedure for reinstallation.

Verified. I've now done this several times in a row while parts-waiting. When reinserting the linkrod into the unit (while simultaneously inserting the unit into its transmission housing orifice)...use needle nose pliers to help center the linkrod into the unit's guide channel, then push the unit down to seat into its orifice. Rotate the unit 90 degrees clockwise to its final position. Affix the clamp.

Then verify the linkrod is latched in its detent-hole position by pulling the opposite end of the Bowden cable. Each pull should be countered by return spring tension. Done.

 

[IslandMon]

The different designs have either zero, one, or two vacuum chambers. The vac chambers are for the E/S program (not used in USA), or the cold upshift delay (used with catalysts). I think if you buy a new one it has both vac pods and you seal off the E/S port when installing on a USA tranny.

I just installed remanufactured transmission and noticed that I have the bowden control pressure unit with the two vac chambers, but the lower one (red one) does not have the vacuum port plugged. I have a black vacuum line plugged into the top vacuum chamber. I ordered the dead end sealing plug for the lower one after I finished the job. Does anyone know if there are any adverse effects of not having this lower vacuum pod sealed off? I will seal it as soon as I can shrink my fingers down to fit in that very tight space, or until the confined space tools arrive in mail, probably the latter.

 

[gsxr]

I just installed remanufactured transmission and noticed that I have the bowden control pressure unit with the two vac chambers, but the lower one (red one) does not have the vacuum port plugged. I have a black vacuum line plugged into the top vacuum chamber. I ordered the dead end sealing plug for the lower one after I finished the job. Does anyone know if there are any adverse effects of not having this lower vacuum pod sealed off? I will seal it as soon as I can shrink my fingers down to fit in that very tight space, or until the confined space tools arrive in mail, probably the latter.

Nothing to worry about, the cap is just to keep dust & dirt out of the unused chamber.