changing clutch slave/bleeding?

[KFunk740]

Any tips on changing the clutch slave cylinder? 

 

I took off to get firewood the other day, and there was barely any pressure in the clutch.  Checked the fluid, and it was dry (except for a layer of 'mud' which made it look like it was full if you were just looking from the outside, doh!).  I topped off the fluid and pumped the pedal lots of times to get some air out, and it got pressure again, but it needs properly bled.  If I'm going to that trouble, I might as well get a new slave cylinder and really fix the problem.  Everything looks clean around the master cylinder, so gotta be the slave I figure.  I went ahead and ordered a new one for a 521 for $16 (only one I could find listed on RockAuto), hopefully that works.  My truck has a J13 and a stock-ish looking 4-speed, floor shift.  Hopefully all these trucks have similar slave cylinders.

How can I flush that 'mud' out without contaminating stuff?

 

It should arrive tonight, and I'll try to swap it out real quick and bleed it.  I suppose I need to adjust it some, will have to dig out the manual and figure that out.  

 

Thanks for any help. 

[datzenmike]

Flush all that crap out of the master before connecting the slave up. That 'mud' is dissolved rubber from the seals so the master will likely still work fine but ...? Brake components use rubber or perhape neoprene/urethane seals that are fine in brake fluid but water is absorbed and so the fluid should be changed every 3-5 years to prevent corrosion of the steel lines. 

[KFunk740]

OK, but how?  I've got a big bottle of brake fluid, but if I just pour it in and push it out, I bet that stuff will still be stuck to the sides of the reservoir.  Would it be safe to use a bottle brush in it, and then flush it out some more?

[datzenmike]

Don't see why not. FSManuals recommend never remove the plastic reservoirs. Not sure why. I have, but I warmed the plastic first before tightening the wire clamp. No problems.

[KFunk740]

That didn't go as well as planned.

 

Well, I got it out OK.  I flushed the fluid lots of times, and scrubbed reservoir with bottle brush.  At least I found some use for some of my leftover big bottle of opened brake fluid.  

 

I go to put new slave cylinder in, and realize its catching because there's an extra ear sticking off the side of it.  Well, no problem, grinder fixed that.  Then I got it in place, and couldn't get bolts to thread in.  Then I realize the bolt holes are just a tad wider on the tranny than on the new slave cylinder.  Well crap, no fixin that easily.  I reassambled it with the old slave cylinder.  I changed the rubber boot and bleeder to those from the new one, at least.  I bled and bled, a whole lot of fluid, and for some reason the fluid still looked foamy.  No idea why, but I was runnin low on fluid and had to call it quits.  It did OK on a test drive.  I'm not quite sure if the engagement point is at the right place, hard to tell.  Hopefully it doesn't get too bad once its hot and any air bubbles expand.

I'll have to drive it some more and see how it does, and monitor the leak rate.  If I have to, I could put in super blue brake fluid, which is so thick it stopped a clutch leak entirely on my BMW.

 

To do it right, I'll have to figure out how to find a real slave for a 320, or at least a rebuild kit. 

[datzenmike]

Foam may be air sucked in on the back stroke? It might just need to sit and become one big bubble you can bleed out.

 

Drill out the new slave holes?

[KFunk740]

It did OK driving to work today, so it should be OK for a while.  No sign of leaks.

 

I checked the 320 parts catalog and found some extra info here:

http://community.ratsun.net/topic/17505-320-slave-swap-question/

 

In the parts catalog it shows 30620-02700 , but that number doesn't work at all when I ask the dealership.  In that thread I found the 30620-32200 number, which does turn up the right part at the Nissan dealership.  But, it shows 'vender restriction, not available.'  Some places online list it as available, but I bet it'd be like my past experiences where the order goes through, and a couple days later they tell me 'sorry.' 

I haven't tried those part numbers for rebuild kits yet, maybe that'd turn up something available.  I'm sure there's someone out there that could find generic parts to rebuild it if necessary.

 

Yeah if I'm really stuck, I'll just have to drill out that 521 slave.  I would end up with really wide slots instead of neat holes, and I don't know how that slop room might allow the slave to wiggle some when it pushes, but I suppose I'll figure out a way to make it solid if necessary. 

[KFunk740]

This one here looks like it could be right, but its not the exact part number, and I'm not sure how far apart the bolt holes are: http://www.ebay.com.au/itm/30620-V6300-Car-Vehicle-Clutch-Slave-Cylinder-Repair-Part-/400728826979?pt=AU_Car_Parts_Accessories&hash=item5d4d4ca463