Aisin Slave Cylinder Spring Question: (1 Viewer)

[GS 60]

Hi
First time she has let me down in over three years!
Clutch Slave gave way on Motorway yesterday.

Question:
Should the Aisin Slave Cylinder have a spring (in the cylinder housing, not talking about the external return spring), see photos below, note scoring on one side of cylinder.
Have ordered a replacement in any case, just wondering could I use this as a spare?

Many thanks

 

[GS 60]

Also, any hints on getting the clutch fork boot on!!!

 

[65swb45]

Not familiar with that exact cylinder; wag it’s a diesel.

In any event, I’ve never seen a slave with an internal spring. Form follows function, and there is no logical reason for one.

The biased wear is a sign that either the tolerances between the piston and bore are incorrect, or less likely, that the load on the cylinder is biased.

Ordinarily I would not even consider the second theory. But our domestic slave cylinders all have much longer bores, so the pistons move easily down a long hole. But since your piston is almost as long as your cylinder, any bias in the load has more of a chance of affecting the piston when it is in use, close to the edge.

 

[pb4ugo]

I've run across a few slave cyldrs with internal springs in them and have run across some that don't. My spare, a new aisin slave has a spring in it.

 

[Coolerman]

I started to reply that my original clutch slave cylinder used a spring but after looking at old pics of it, turns out my slave cylinder was made by Miyaco and is a 3/4" with an internal spring...

 

[GS 60]

Thanks Guys, fitted a new slave today, will keep the old one as spare anyway, probably just buy a repair kit for it.

Thanks again

 

[Splangy]

That’s a BJ42 cylinder and should not have an internal spring. I’m pretty sure I recently bought a new spring from Toyota for a truck I’m building. If you need something to get you by, you shouldn’t have a hard time finding something that will fit at your local mom & pop hardware store.

Those BJ boots can be a real PITA to install, but they’re one of those parts that fights with you a dozen times and then you catch it just right and it suddenly goes in easy.

 

[GS 60]

Thanks for that, got a new slave fitted earlier today. Will hold onto this one as a spare.

 

[middlecalf]

Well my curiosity is peaked. Is that internal spring referred to in earlier posts a compression spring or a tension spring? If compression, which seems to fit an internal design, I’m befuddled as that would push the clutch fork toward the clutch plate and would mean a new throwout bearing every few thousand miles, or even kilometers. Maybe another Guinness will help me see this design functionality. I doubt it.

 

[DougAustinTx]

My '79 has an internal spring in the Aisin clutch slave. It pushes the plunger out a short distance, but if the linkage is properly set, it does not put any pressure on the throw-out bearing. Even if it did put pressure on the throw-out bearing, I have read that the OEM Toyota T-O bearings in our trucks are designed to survive constant contact with the pressure plate fingers without damaging the TO bearing. Lots of Triumph TR6 drivers have replaced their British T-O bearing with the FJ40 T-O bearing because the Triumph linkage design allows constant bearing contact with the pressure plate and the Toyota units have been found to tolerate it better. ( I also have a '76 TR6 that was designed to allow the T-O bearing to be in constant contact, but I redesigned my linkage to avoid the contact.) Seems kind of stupid to have the bearing rotating all the time, and possibly wearing out the fingers on the pressure plate.