MT Accumulator Delete Mod (ADM) and BS Thread

Did the prefab brake line first last week, the disc came in earlier than expected yesterday and switched it over last night. Gonna drive it for a bit with the disc to better assess which one I might like better.

 

Probably have some air still in there. I’ve driven the dremel method and the hose method and both felt the same. In my experience, no matter how much bleeding happens at the slave, there always seems to be some air in the system anyways that works itself out in a day or two with some use. My guess is what is what you are experiencing with the disc. But I guess time will tell.

 

Appreciate the feedback, and air still being in there was one of my suspicions as well. The engagement point being different between the two was what I really didn't expect.

 

Yeah, no matter what method is utilized, feel or engagement point shouldn’t change much. Even the accumulator being in place shouldn’t change the engagement point much, it just makes it vary a bit which makes it feel inconsistent and spongy.

 

I will say that the Slave Spring mod has permanently changed the engage point. Comfortably closer to the floor. Confirming that nothing on the ADM should feel different and that the clutch self bleeds nicely. If you can shift after finishing up, it will take a few days to fully settle out all by itself.

 

Agreed with all the above, my top half of the pedal travel had no resistance to it at all for 2 days. Gradually went back to being normal by day 5. This despite excessively bleeding the clutch to make sure there was no remaining air.

Huge thank you to Firn, quality was amazing, the clutch now feels as it should, and I’m relieved I did it now after realizing how much the accumulator was slipping the clutch

 

wait so which version of the delete do you think was better, the disc or the hard brake line? I know you say they both achieve the same.thing, but which did you like more? I have the disc, but I feel at times like the engagement is not where i think or would want it to be. Ive been considering doing the hard line instead...

 

I did mine Aug 19 and even after bleeding multiple times I did think pedal felt softer, engagement was closer to the floor. I had no issues driving it though. Yesterday Aug 27 I jumped in my truck and it must have worked some air up because the pedal was back to original firmness. Now the clutch feels even better.

 

I think it’s mostly due to it being a clutch design vs a brake design. We’re used to what brakes do when you bleed them and expect the same behavior. The difference is, a brake caliper piston extends over time as pads wear, meaning there is nothing pushing fluid back up to the master cylinder.

A slave cylinder is never going to extend more than the same amount, every time. While on the flip side, the clutch wearing actually pushes the slave further and further inward since the slave/fork/TOB/clutch are always touching. So kind of like a syringe, the fluid in the slave will actually be lessened over time as the clutch wears and it will push the fluid out of the slave and up through the master to the reservoir. Which should actually constantly self bleed. The reservoir should basically gain fluid over time as the clutch wears, and as part of that it should bleed its air out. I think this is also why “bleeding” never gets all the air out, because it’s counter intuitive to what we think it is doing. I dunno, just my hypothesis.

 

It depends. The first few times I messed around with accumulators, the clutch felt spot on afterward. No idea why the last handful had some air in. But as we know, it is no big deal.

You are right that wear is opposite for clutches with respect to fluid volume.

All hydraulic systems are the same with a compensation port in the master at the very end of the travel. As long as that is properly open / unblocked, the systems can breathe and bleed. I think the clutches are likely designed with no low spots to self bleed like this. The bubbles just rise until they hit the reservoir.

It is easier to see on motorcycles, but there will be a disturbance in the res as the open compensation port tosses some fluid back into the res just as it closes. There are many stories of folks going down after installing new levers because they didn't set the rest position properly. This is why most all stock lever set screws are glued over from the factory.

 

I have no way to explain how sometimes it turns out okay and other times has air, I do know though that the 3 times I have opened up my clutch hydraulics (accumulator, FJ Pedal install (faux), FJ Pedal install (for real)), all 3 times left me with air. The accumulator time probably left me with the least amount of air, and that time was me and my brother bleeding it the 2-man way. Both of the FJ pedal occasions I was by myself, so I just let it gravity bleed for a bit and then just pumped the pedal a bunch of times until it was drivable, and it worked the rest out on its own in a day or two.

 

Exactly. As long as you can actually shift and not drag the clutch when done, then that is good enough. I absolutely enjoy that.

 

I too have been wanting a short throw since this mod Scrolling that Core shifter thread until I saw the pricetag....

 

I think toward the end of that thread, there is another option that is similar and less expensive?

 

Well, I wouldn't say one is 'better' than the other, they both accomplish the same goal of positive and consistent clutch engagement. It was more that the pedal feel after installing the disc was so different. Personally I prefer a constant linear pressure in a clutch pedal (including the backstroke) instead of having some soft/dead spots or a weak pedal return.

After ~30 miles of running errands yesterday, I can confirm that there was/is air in the system. About half of the dead spot is gone now and the reservoir dipped down a bit. Right now, I'm going to stick with the disc and probably get some LV fluid since I have experienced the pedal stick on some cold mornings. The reports of a prefab hard line possibly leaking was a concern long term, I am just impatient and wanted to try the delete while waiting on the disc to arrive (another big thanks to Firn for creating that piece).

Also, curiosity got the better of me last night and did a little learning on hydraulic pressure and flow and delved a bit into Bernoulli's principle. My original thought was that having a large cavity (the accumulator) in the system would affect the pressure of the overall system (giving a different pedal feel) but that doesn't seem to be the case. However, a section that restricts the fluid flow can actually drop the pressure and create a vacuum. Others with more knowledge on this can correct me if I'm wrong but I think that is what may cause the spongy feel with the stock accumulator.

 

It is a bit cheaper than the B&M though.

That chrome stick after I just deleted all the chrome in the interior...

This is why it never ends...

 

I would speculate it's because of how the accumulator is designed. With the inlet/outlet ports being on the center of the circular cavity there is going to be a potential air pocket above them. Similar things can happen in radiators/cooling blocks when liquid cooling computers if they aren't put into an optimal orientation when initially filling them.

 

Good point.

 

I'm still working my way through that large thread, day by day lol!

 

Cheers! Lots of posts there. I think the B&M that was noted is what I was trying to remember. I also thought it was less than the Core, but things might have changed.

That's a lot of dosh, but I do like that is doesn't have the stupid chrome shaft:

https://urdusa.com/bm-shifter-16-tacoma-v6/