Gear Selection / Clutch Adjustment?

[mcgc0]

Seems to be my week of minor challenges.. For no apparent reason and with no degradation signs I am unable to select 1st, 2nd or reverse gears. Without the engine on I can select the gears - although a little tight. When on the move (having moved off in 3rd) it can be done but it's bloody difficult.

My clutch biting point seems like less than an inch from the floor. Only thing that has been done in that area is me removing the pedal board to teflon spray the nylon clutch bush that was squeaking every time the pedal was depressed. This was done the week previous and the car changed gear fine after an hour's traffic driving. However, in drawing a template of the pedal board (Al replacement sometime in the future) I removed the pedal stop attached to the board but carefully replaced it in it's same position.

The only thing I can think of is maybe this slipped a tad, but if this was out of adjustment wouldn't it affect any gear selection? I will check the stop anyway and try to measure the the pedal travel to the spec (145mm +10).

Need to ask too about the clutch fluid top-up to make sure this isn't the problem; With a C4 (1990), and the larger shared reservoir with the brake fluid, I noticed the level barely above the Min marker (after following the correct engine start, pump brake, allow for pump to stop running, check fluid level, procedure). Would just this small amount of level change affect the clutch, and then again just for the low-end gear selection? I will need to top up the fluid I guess and hoping I can use any DOT4 plus (but not 5) from, say Halfords or does it have to be something from Porsheshop?

Should mention a new RS clutch and flywheel were fitted back end of 2008 at RPM Tecknik so don't suspect actual clutch issues..

 

[Steve Brookes]

When mine developed a problem of selecting 1st gear, bleeding the clutch slave solved it.

 

[mcgc0]

Interesting Steve, thanks. Accessible enough from underneath the car or any special tools? Is it the usual pumping of the clutch while bleeding?

Cheers

 

[Steve Brookes]

ORIGINAL: mcgc0

Interesting Steve, thanks. Accessible enough from underneath the car or any special tools? Is it the usual pumping of the clutch while bleeding?

Cheers

Yes it's accessible by jacking up and removing the left rear. But you need bendy arms and a good touch because it's almost impossible to see.

Bleed only with a pressure bleeder. Do NOT use the old foot pumping method. You shouldn't do that on the brakes either. I can't remember if your is C2 or C4....the reason I ask is I believe the C4 brake/clutch fluid system is more complex and bleeding often involves a Hammer for some reason. I don't know if that's also needed when bleeding the clutch slave but hopefully someone else will have info on that for you.

 

[mcgc0]

Thanks Steve, I knew that brake bleeding was not of the usual convention but wasn't sure re clutch - I'll check up in the workshop manual.

It's a C4. The pressure bleeder you mention I'll also need to check (is it a tool or a a component of the slave cylinder - e.g. simple nipple?)

 

[Dave Wilkinson]

Marcus,

The pressure bleeder is a device which is attached to the fluid reservoir to provide a sustained air pressure through the fluid supply route as an alternative to the "pedal push" you refer to. The system used on both the C2 and C4 doesn't work well with the "pedal push" method as it can lead to the ingress of air into the system and defeat the object of the bleed. The pressure bleeder most recommended on Rennlist is the one from Motive (see here) although I don't know if the same device is available in the UK. Other makes certainly are.

The "hammer" involvement is only required on the C4 if you are intending to bleed the diff lock actuators. In order to bleed them effectively, Porsche recommend pulsing the actuators quite rapidly and there is a program built into the Bosch tester to faciltate this function. Otherwise, for brake and clutch bleeding, the "hammer" isn't required.

Regards

Dave

 

[mcgc0]

I see now - thanks. I'll search around for a pressure bleeder locally.

How about the fuild then; good to go for a standard DOT 4 plus as in Halfords or get a litre from Porscheshop/similar?

 

[vitesse]

ORIGINAL: Dave Wilkinson

Marcus,

The pressure bleeder is a device which is attached to the fluid reservoir to provide a sustained air pressure through the fluid supply route as an alternative to the "pedal push" you refer to. The system used on both the C2 and C4 doesn't work well with the "pedal push" method as it can lead to the ingress of air into the system and defeat the object of the bleed. The pressure bleeder most recommended on Rennlist is the one from Motive (see here) although I don't know if the same device is available in the UK. Other makes certainly are.

The "hammer" involvement is only required on the C4 if you are intending to bleed the diff lock actuators. In order to bleed them effectively, Porsche recommend pulsing the actuators quite rapidly and there is a program built into the Bosch tester to faciltate this function. Otherwise, for brake and clutch bleeding, the "hammer" isn't required.

Regards

Dave

Surely you mean " sustained fluid" pressure-all these pressure bleeders work on the basis of maintaining the top fluid under pressure to ensure that the fluid level doesn't drop below minimum(as when topping up between pedal strokes) & continuity of fluid throughout the process-air only comes into the equation as a means of pressurising the fluid in the top-up bottle sometimes from the spare wheel.

 

[Dave Wilkinson]

Colin,

I think we're on the same page!! I only used "air pressure" as it's air that provides the pressure within the pressure bleeder to apply pressure to the fluid. The Motive unit actually has it's own manual pump but, as you say, there are other units that make use of the pressure in the spare tyre to provide the same function.

Regards

Dave

 

[mcgc0]

I've looked around and have now ordered the Sealey unit below. This maintains the air pressure on the fluid using the tyre which can be valve controlled. Also ordered a litre of Porsche fluid from Porscheshop knowing that DOT 4 from Halfords would probably serve just as well but wanted peace of mind should it become a factor..

http://www.ccw-tools.com/uploads/images_products/25748.jpg

 

[Steve Brookes]

Marcus, I use the eezibleed kit which looks much the same as the Sealey device in your picture. Very easy to use but the most important point to remember is clamp off the overflow pipe on the reservoir otherwise the pressue will force all the fluid onto the floor!

These pics might help:

The slave bleed nipple needs a 7 mm spanner - get a hex one like mine below as a ring spanner will just round off the valve:

BTW the jar contains the dirty old fluid trapped in my clutch slave.

 

[mcgc0]

Excellent stuff Steve and thanks for the tips. Will let you know how it went..

Can see from your reservoir that it's a C2 then, mine is almost half as wide again.

 

[Steve Brookes]

Some other tips when using the pressure bleeder for the first time:

1. DO let your tyre down to 20 psi or a little less as they say.
2. Connect up the empty bottle first to check you have a good seal when connected to the tyre i.e. this checks your overflow is clamped enough.
3. You CAN at this stage use the empty bottle to push fluid through the system (when you've opened a bleed valve) but DON'T let the main reservoir go below the MIN line.
4. When you decide to put new fluid in the bottle, don't worry if it all seems to gush straight into the reservoir when connecting the tyre. That's normal.
5. If fluid seems to be going through the system too fast and getting dangerously close to the reservoir MIN line....don't panic....shut the bleed valve you have open and undo the pressure hose at the tyre and work out what is going wrong.

Good luck []

 

[kevin]

My bet is twofold, either the clutch slave is going south due to wear and tear because it hasn't been done (under the too difficult page) or you need a new clutch, I needed a new clutch as I found out when I replaced my slave.

kevin

 

[mcgc0]

Hoping the former if it has to be one of the two as it had a new RS clutch and flywheel fitted less than 4k miles ago. Let's see what bleeding the clutch does this weekend... fingers crossed.

 

[kevin]

ORIGINAL: mcgc0

Hoping the former if it has to be one of the two as it had a new RS clutch and flywheel fitted less than 4k miles ago. Let's see what bleeding the clutch does this weekend... fingers crossed.

Ahh, in that case was the slave replaced? flushed? or the pedals realligned, there is adjustment on the pedal box, and that has been known to cause issues with improper adjustment..

kevin

 

[mcgc0]

Good questions Kevin. Going through the Tognola receipt I have, the clutch slave cylinder was replaced 37k miles ago along with associated piping/hoses. 4k miles ago RPM did the menu 24k mile service with a brake bleed.

While I am prepped up for a clutch bleed, I will do initial checks on the pedal board clutch stop (as I had that off the other week) and check/measure the correct travel as per workshop manual. I did notice when following the correct fluid level checks that the reservoir was down to only just touching the min mark. I did hear somewhere that even a small change in level can make a difference, so I shall be topping that up accordingly.

Marcus

 

[mcgc0]

Have all gears now with clutch working fine as intended.

Had prepared (and equipped) myself for a full clutch bleed but went through first some of the more obvious (and easiest) tasks. Topped up the reservoir to 1+mm just below the max market - now have full clutch engagement.

Became familiar with the foot-well again and took out the pedal board to replace the U nuts that rusted away as the securing screws didn't seem to keep the board in place tightly enough. Tried measuring the pedal clutch travel but gave up after 30 mins is it ain't easy depressing the clutch and at the same time measuring the travel. Adjust the pedal arm stop instead to where I felt it needed to be.

On replacing the samall sqaure pedal carpet piece I noticed that the slot in the carpet for the pedal had not been in the past where it should have been. The carpet had slipped down meaning part of the carpet and piping had got in the way of full pedal travel with the pedal arm pressing against this rather than the board stop. Carpet back out and a Stanley knife to lengthen the slot and remove some of the piping. Securely back in place with those little corner straps properly tightened to the brackets and everything worked much better.

Will probably do a full clutch bleed soon anyway, but at least don't have to worry about that being the cause of my problem.

 

[polar964]

Pleased that it was a simple solution for you Marcus.

 

[mcgc0]

Thanks Paul. I'm always aware that something else might rear it's ugly head before long - hope it's no longer the clutch. Trying to make sure all is ok for the annual pilgrimage to Le Mans..