New Luk clutch engagement

[Skooby]

My son just installed a new luk clutch kit (non self adjusting). The engagement point is right at the floor. We have the system bled for sure and it goes in and out of gear now with no grinding into reverse like it did before it was bled properly but the engagement is literally right as you lift off the floor. Ive read in some other forums that with the no self adjusting plates this is normal and the engagement point will move up as the new disc wears. Is this truly normal for this type of set up? Thanks in advance!

 

[franklin2]

It will be a radical difference in release position if you compare it to the old worn out clutch position. Drive it some and see if he gets used to it. Plus, if there happens to be a tiny bit of air left, driving it will promote that to eventually leave, and the position may get even better.

 

[bobbywalter]

hard to say. i know if it was doing that i would assume i still had air or mismatched master/slave situation.

 

[Skooby]

hard to say. i know if it was doing that i would assume i still had air or mismatched master/slave situation.

Slave and master were not changed, only the clutch parts and the flywheel was surfaced

 

[gaz]

@Skooby
I've put 3 different style clutches in the 1st gen chassis, the clutch engagement point never changed, only the pressure required to depress the pedal changed with clutch performance level:
1) OEM replacement
2) upgraded aftermarket, Centerforce
3) Zoom, stage 2 Kevlar

 

[franklin2]

@Skooby
I've put 3 different style clutches in the 1st gen chassis, the clutch engagement point never changed, only the pressure required to depress the pedal changed with clutch performance level:
1) OEM replacement
2) upgraded aftermarket, Centerforce
3) Zoom, tage 2 Kevlar

If the clutch that was in there was wore out, the engagement will change. As the disc wears the fingers in the pressure plate protrude further out of the pressure plate.

 

[Skooby]

New development. Was as I described b4 clutch felt good, air bled, going into gear no problem, low engagement point. He moved it out of the shop for the first time since the work, got out to check clearance behind the truck, left it running in N, when he got back in clutch felt spongy again like it has air and can't get it into gear. Ffs this shouldnt be that hard.

 

[franklin2]

New development. Was as I described b4 clutch felt good, air bled, going into gear no problem, low engagement point. He moved it out of the shop for the first time since the work, got out to check clearance behind the truck, left it running in N, when he got back in clutch felt spongy again like it has air and can't get it into gear. Ffs this shouldnt be that hard.

These hydraulic clutch systems can be very difficult to get the air out. I believe you have gotten most of the air out already. What works most of the time is to drive it on a bumpy road. If you can plan your route, you can warm the engine up so it runs well, and then turn it off and put it in gear. Start the engine and go. Use the clutch and shift through the gears going down the road. The clutch should eventually get better as the air migrates backwards up into the clutch master reservoir. If the clutch is not working and you have to stop, just turn the truck off. Put it in gear and when you need to go, start the engine and go. If you have a decent back road with not much traffic, it should not take long at all for it to start working the air out.

I only had to go around the block and my clutch started working.

 

[Bill]

Ford had a TSB explaining why air gets trapped in the hydraulic system and how to bleed it. The graphic on page 5 shows where the air gets trapped when the master cylinder is installed. I think mine may have air trapped in it. Sometimes mine is hard to get into gear and there is a slight "clash" when I'm shifting while moving.

Adding this TSB to the technical resources for future reference would help a lot of people bleed the system the correct way.

 

[SenorNoob]

Just thinking out loud here, but if the slave nor master were changed, why was it bled any? The quick disconnect should make that unnecessary.

 

[4x4junkie]

These hydraulic clutch systems can be very difficult to get the air out. I believe you have gotten most of the air out already. What works most of the time is to drive it on a bumpy road. If you can plan your route, you can warm the engine up so it runs well, and then turn it off and put it in gear. Start the engine and go. Use the clutch and shift through the gears going down the road. The clutch should eventually get better as the air migrates backwards up into the clutch master reservoir. If the clutch is not working and you have to stop, just turn the truck off. Put it in gear and when you need to go, start the engine and go. If you have a decent back road with not much traffic, it should not take long at all for it to start working the air out.

I only had to go around the block and my clutch started working.

This has always been my experience as well. As long as it is driveable, when you drive it, the clutch pedal should come back up to normal.

Also, (excepting for this particular scenario here) the clutch pedal position under normal circumstances should never change. As the clutch disc wears and the PP fingers move outward, it pushes the slave cyl inward (the excess fluid bypasses the master and gets pushed up into the reservoir). When you step on the pedal, it closes the bypass and operates the clutch from the same point in the pedal's travel as before. It is effectively a self-adjusting system (unlike an older cable-operated clutch).

Just thinking out loud here, but if the slave nor master were changed, why was it bled any? The quick disconnect should make that unnecessary.

Good question. Maybe the fitting is imperfect and a tiny bit of air still got in? If the bubble managed to get up into the master cyl, I could see causing this. But again, if it's driveable (even for briefly), as long as the bubble isn't in the slave itself (where it's easy to eliminate it by opening the bleeder), it should work it's way out.

Interesting that TSB article @Bill posted... I actually figured out on my own I could bleed these things enough to get them working without having to remove & bench-bleed the master by rapidly stomping on the pedal a bunch of times to purge that air pocket. Funny to find the TSB says to do the same thing. lol

 

[Bill]

Interesting that TSB article @Bill posted... I actually figured out on my own I could bleed these things enough to get them working without having to remove & bench-bleed the master by rapidly stomping on the pedal a bunch of times to purge that air pocket. Funny to find the TSB says to do the same thing. lol

That procedure isn't going to get air out of the master cylinder while it is installed. If air is trapped in the master cylinder the only way to get the air out is to turn it upside down so the air can move out of the master cylinder.

 

[Skooby]

End result- I'm pretty sure we had it bled out ok, the problem was intermittent toward the end and only when my son was trying. So.......I got under the dash and started looking and I noticed that if there was any lateral pressure on the pedal to the left the pedal shank would land on the end of the master cylinder mount bolt eliminating a good 3/4to an inch of travel I pushed the pedal toward the brake a bit and trimmed the back the firewall insulation where it touched and it's been normal since

 

[4x4junkie]

That procedure isn't going to get air out of the master cylinder while it is installed. If air is trapped in the master cylinder the only way to get the air out is to turn it upside down so the air can move out of the master cylinder.

So what you're saying is what happened could not happen?? (and that the TSB is wrong?) Because it did happen...

 

[Bill]

So what you're saying is what happened could not happen?? (and that the TSB is wrong?) Because it did happen..

Read the TSB again. That procedure is for the slave cylinder, or if air is in the line downstream from the master cylinder. Now look at the master cylinder diagram on the last page that shows where air gets trapped. You aren't going to get air out of the master cylinder unless the air can exit the master cylinder through one of the two lines, which isn't going to happen with it installed. If you bled your hydraulic system by pumping the pedal it was becuase the air was somewhere else other than in the master cylinder.