SPF Slave Cylinder Help. - Page 2

Got the Bug · #21 (**permalink**) 02-05-2010, 12:45 PM

Quote:

Originally Posted by jhv48

I took it to a local mechanic that does most of my normal engine work and showed him what I had done. He kept it the whole day and whenI picked it up said he couldn't get reverse to grind once and that the clutch was not dragging at all.

I got in it to drive home and started the engine with the clutch pedal to the floor, shifted into 4th and then slowly tried reverse..........GRIND.

What am I doing wrong?

Strange. I guess the next step is to have a fellow Cobra owner with a similar configuration sit in your car and attempt to put it into reverse. I leave my car parked in 3rd, but usually put into first, then neutral, then reverse.

jhv48 · #22 (**permalink**) 02-05-2010, 12:55 PM

Hand grenade in driver's seat.

Pull pin, walk away.

Start all over again.

Blittleton · #23 (**permalink**) 02-05-2010, 01:56 PM

Jim,

This isn't rocket science. A couple things could be happening here. Either your Clutch Master is bypassing a little, or your clutch may be worn enough were you don't have enough throw. Has this always been the case with grinding? What has changed? Did you try the adjustment rod I mentioned?

Bill

jhv48 · #24 (**permalink**) 02-06-2010, 10:24 AM

Car has 2000 miles on it and it just started.

I did the adjustable rod and used it to take all the freeplay out of the adjustment.

Slave travels about an inch and a half.

Clutch is not dragging in any way. Full disengage about 2 inches from the floor.

Going to just drive it and get used to it!

Rick Parker · #25 (**permalink**) 02-06-2010, 01:07 PM

Depending if you have a push or pull type slave and before you adjust the rod; push or pull the rod in the slave so the piston is able to compete full travel. If it is a pull type, be sure it is fully extended. If it is a push type be sure the piston is completely bottomed out in its bore, THEN adjust the rod, this will then allow full travel of the piston. Doing this will displace fluid from the slave into the master resevour so allow room for it. If this is not done the piston may not be moving far enough to effect full release of the clutch.

For the record how much free travel are you allowing at the clutch release lever and adjusting rod?

jhv48 · #26 (**permalink**) 02-06-2010, 04:36 PM

Did that. I added a threaded rod to my slave (pusher) and pushed the plunger as far back as it would go. Then adjusted the threaded rod so there was 0 freeplay on the fork.

Clutch disengages just fine. Tranny grinds in reverse.

Maybe it's just me!

madmaxx · #27 (**permalink**) 02-06-2010, 05:53 PM

TKO 600 are a little notchy but should never grind in a forward gear. Reverse will unless go to a forward gear first. Do not force in the reverse, strange problem

cdnus · #28 (**permalink**) 02-06-2010, 06:18 PM

jvh48

Seeing as you have checked most everything, here are some thoughts from someone not standing in the forest.
You may have a dry or tight pilot bearing, a disc spline sticking on the spline (tight or no lube)or a warped disc. All of which can cause enough drag to spin the input shaft enough to cause grinding into reverse, but not felt when checking. All forward gears are syncro so no grinding.
Hope this may be of some help.

Craig

maxum_101 · #29 (**permalink**) 02-06-2010, 07:37 PM

Quote:

Originally Posted by Rick Parker

Depending if you have a push or pull type slave and before you adjust the rod; push or pull the rod in the slave so the piston is able to compete full travel. If it is a pull type, be sure it is fully extended. If it is a push type be sure the piston is completely bottomed out in its bore, THEN adjust the rod, this will then allow full travel of the piston. Doing this will displace fluid from the slave into the master resevour so allow room for it. If this is not done the piston may not be moving far enough to effect full release of the clutch.

For the record how much free travel are you allowing at the clutch release lever and adjusting rod?

ok i got a question when i remove my slave from the bracket and the fork my slave will keep pushing the rod out, not a little bit but for a good distance almost seems like the full travel of the cyl. is that normal? ive tried bleeding the slave many times and it still does the same thing i ask this cause my slave is alway pushing on the fork causing the t/o bearing to press on the pressure plate. dont know if i have a problem somewhere or if my slave is defective.

jhv48 · #30 (**permalink**) 02-06-2010, 07:42 PM

Maxum, that's normal. There is an internal spring that pushes the rod all the way out all by itself. You can push it all the way back in with some effort.

Completely normal. It will exert constant pressure on the fork, but not enough to cause any engagement. Meant to be that way. Kind of self adjusting. I pulled out the rod and put in a threaded rod with lock nuts on either side of the fork. This way I control exactly when the fork starts moving.

Still grinds in reverse though!

Silverback51 · #31 (**permalink**) 02-07-2010, 06:18 AM

I had problems with mine dragging, and to eliminate that, I had to adjust the rod so that I was preloading the throw out bearing. Neither condition was acceptable in my opinion.

I had a 1 inch diameter slave cylinder, so took some 1 inch diameter stainless material I had in the garage and bored a 7/8 inch diameter sleeve to fit in the existing slave cylinder to get more stroke. Just got it completed yesterday and it works like a charm. No drag and no preload on the throw out bearing.

It does have a little more pedal pressure, but not that bad. I can live with it.

And sorry, I did not take any pictures while I was doing it. I have a spare slave cylinder here and I'm probably going to make up a spare in the next month or two. I will get pictures of that one if anyone is interested.

madmaxx · #32 (**permalink**) 02-07-2010, 07:18 AM

Preloading the throwout bearing is not an issue, most new cars, mustangs they are preloaded. It seams GCPC slave cylinder set up would eliminate adjustment issues since it has so much adjustment mechansims built in.

jhv48 · #33 (**permalink**) 02-26-2010, 03:34 PM

Solution to the grinding in reverse problem:

It took me two months of trying different fixes but it was a defective pilot bushing. For some reason, it wasn't allowing the input shaft to stop rotating when the clutch was disengaged so there was no way to stop the internals from spinning with the clutch in.

Replaced only the pilot bushing and reassembled the drive train with all the old parts and the shifts are effortless now.

$15 part cost me $1000 to diagnose and fix!

madmaxx · #34 (**permalink**) 02-26-2010, 04:01 PM

Thanks for the feedback!!!!!!!!! great information. I wonder how you could test the pilot bearing without taking everything apart.

snakebitekit · #35 (**permalink**) 02-26-2010, 04:31 PM

I recently went through almost everything you are describing. Replaced the slave, still had the problem. When I replaced the master the problem went away. What apparenly happended when the system was working at the mimimum i.e. you push in the clutch you could shift but barely, and reverse you have to go though 1st first to get in reverse. What happened to mine was I blew the seals in the master from the pressure of the pedal, as little as it was it lessened the pressure.The leak was all internal with no leaks visable to the exterior. Once I replaced the master and re-bled it worked better than ever. It was bleeding back into the system.
Prior advice is true, make sure the piston on the slave is pushed in all the way. If your not using a push type bleeder you are creating more work for yourself than necessary. My master was $65.00, it worked and now I have a rebuilt spare. ERA uses BMW slave and master cylinders.
Dennis