I think the quality of the cylinders are just crap. Air has to be sneaking in through the seals somewhere. Maybe not enough to let fluid out but even the tiniest bit of bubbles just screws up the entire system. It's not forgiving at all. No one has figured out yet why the transmission locks up. Previous Wrangler generations don't do that. If you push the stick a little harder it will eventually go into gear on a JK. With the JL no amount of force will get it to go into gear when the disc is dragging - it just locks you out of gear.
This was what I found after just an hour. But there’s not really any way of telling where exactly the bubbles came from. If air is getting in, you would think fluid would be getting out somewhere. Unless the vacuum somehow pulled air beyond a seal at the master or slave cylinder.
As a mechanic, there has to be a rational explanation for this. Nothing just stops working properly for no reason lol. That being said, has anyone else noticed the big curly-Q in the exhaust adjacent to the slave cylinder?
That may be next on my agenda. I haven’t been fully locked out yet, knock on wood. I’ve also given some thought to digging in my toy-box at work and rigging up a one-way hose situation for bleeding purposes. My initial fear with pulling a vacuum was if the hydraulics are garbage, then it would undoubtably suck new air in.
I may get poked fun of for saying this, but does anybody know if the Tremec 6060 will fit in a JL? Asking for a friend…
I was just thinking the same thing. I was curious if anyone had tried reaching out to vendors to see if they can do a manual transmission swap. Seems like that would be a better solution than trying to polish a turd. There are vendors that will do complete engine/transmission swaps, so I don't see why just a transmission swap wouldn't be feasible.
Yes, this is the rabbit hole I had in mind. I’m glad you said something about the 3160. It’s just a bummer we even have to think of this being an option. If one of the main issues in the JL is the hydraulics, would the whole different clutch/cylinder shooting match with the TR-3160 be compatible?
I am really in over my head on this topic, which is why I was inquiring if anybody had looked into it lol. My guess is that EVERYTHING would need to be swapped to ensure that the transmission operated smoothly. Master cylinder, slave cylinder, clutch components, etc.
I tried a pressure bleeder also and it wasn't very effective. I think the best bleed I ever got was pumping up the pedal, holding it down with a 2x4 and jumping under the Jeep and opening the bleeder. I think I ended up doing that for almost an hour while also making sure to top off the fluid.I tried something a little different this afternoon in another attempt to bleed my clutch hydraulics. In my shop at work I have a pressure bleeder. I’ve been toying around with the idea of hooking it up to the reservoir and cracking the bleeder on the slave cylinder to see if it would make any kind of difference. All it does is force fluid through to expel any air that may be hiding. I’ve only used it once before on a set of brakes that was being impossibly stubborn for some reason, and it worked beautifully. Nothing I have tried thus far has made any change at all positive or negative, so I thought what have I got to lose?
I dialed in the regulator to a safe pressure so I knew I wouldn’t whoof anything and potentially make things worse. Then I ran some fluid through it to get any air out of the hose. I hooked the apparatus up, shimmied under the Jeep, slid a piece of tygon over the nipple and cracked the bleeder valve. I let it run for about five minutes or so and watched the tygon diligently for any air bubbles. When all I saw was clear fluid, I shut ‘er down. Right or wrong, I can’t tell you. But I can tell you this - It did not make any difference at all in my situation. I know these can be tricky to bleed, but it’s not like it’s a massive complicated system. It’s a plastic reservoir, a rubber hose, master cylinder, 3/16 brake line as long as my arm, and a slave cylinder. I would like to think pushing fluid through it for a few minutes would alleviate any air bubbles.
Everything on my Jeep is stock except the turtle on my dash and a few coats of Meguiar’s Cleaner Wax lol. At 5,800 miles and no recalls… I realize the hydraulics are finicky, but I am really leaning towards the problem being something else. I think my next step is going to be getting it on my lift and seeing if I have any type of clutch drag. I had posted a couple of weeks ago in another thread about my harmonic balancer having a little wobble to it. Someone suggested that was normal. I got to talking with my dad and he brought up an interesting point. Should that wobble happen to carry through, could it potentially offset your flywheel enough to make your clutch wear uneven and get something out of balance enough to cause an intermittent shifting issue in a manual transmission vehicle?
Something you would never constantly fight in an automatic with the exception of maybe wearing out a belt or idler prematurely. I am just tossing spaghetti at the wall to see if something eventually sticks
I’ll try it. It’s worth a shot at this point. I was kind of planning on that when my ol’ man suggested the pressure bleeder we had sitting in the corner.
Ya know, I was just wondering the same thing while driving to work this morning. I wouldn’t have thought with only 5,900 miles on the odometer, but stranger things have certainly happened. What I got to thinking between weather and temperature fluctuations here lately, combined with a couple trips to the brushless car wash with the under-body sprayer - If maybe that affected the linkage somehow? Giving it a little shot of lube couldn’t hurt? If anything, it’s another thing to cross off the list.
Looking at it outright not lying on my back with fogged up safety glasses, this totally makes sense now lol.The design of the slave cylinder is poor when it comes to bleeding. The supply line and the bleed port share the same fluid path, air cannot get out of the slave if fluid is flowing through the supply line. Thus a pressure bleeder will do nothing. Here is an illustration of what I am talking about:
The orange line depicts the fluid flow from the master cylinder under normal operation. The green line is the fluid flow when bleeding as described in the FSM. The blue line shows the fluid path when pressure bleeding.
Another thing working against us is the rod end of the slave cylinder is higher than the bleed port when the Jeep is sitting level. Air rises, therefore it will move away from the bleed port.
I had success by jacking the rear of the Jeep up enough so that the bleed port end of the slave cylinder was higher than the rod end. Fully depress the clutch pedal and block it with a 2X4. Then climb under and crack the bleed port open. Close the port, remove the 2X4 and lift the clutch pedal off of the floor (it will not return on its own). This method imitates the procedure described in the FSM without having to pull the slave cylinder from the transmission.
