Mike J

So I occasionally get pulled into solving a puzzle or two. Here is one from today.

One of the guys sends me a message "Help - my clutch pedal is very soft for the first part of being pushed down, then it seems to engage - what do you think"?

The car is a 96 993TT - about 55,000 miles, great shape.

Ok, so he comes into the shop and we have a quick look. The Pentosin reservoir in the trunk is EMPTY. Ok, that is a problem. No signs of leaks, no wet trunk or under the reservoir. We check under the clutch pedal for the slave - dry dry dry. I put the car on the hoist and check out the slave cylinder on the top of the tranny - dry as well. No sign of any wetness anywhere.

Ok, so I fill the reservior, pressure bleed it and get some air bubbles, bleed about three reservoir tanks full and then lock it all down with a full reservoir. Clutch pedal now feels back to normal.

Ok, so I am thinking there are no big leaks since there is no signs of Pentosin on the car, so it must be a very slow leak where the Pentosin is evaporating and not accumulating enough to cause a wet spot or drip. The level of this reservoir has not been checked regularly, so it might have been slowly going down over months before it finally caught some air.

The main Pentosin tank by the engine is at a normal level.

We are now tracking the pentosin "consumption" to see if its a very slow leak.

Anyone every experience this?

Cheers,

Mike

Quadcammer

I had a pentosin leak from the hoses leading to the PS pump.

You couldn't really see it from the top, but the valve cover was wet, and ultimately I had a lake of the stuff on the ground. you could try poking around down there, but to lose a pint+ of fluid and not have it appear anywhere is beyond unusual.

Did you check the steering rack boots for fluid btw?

Mike J

Hmm, this is the low pressure side of the clutch circuit -> the pentosin that was empty was the one in the front trunk. I doubt if the slave cylinder would allow the low pressure side to leak to the high pressure side, but I checked that as well -> the main tank in the engine bay was perfect, no leaks on any PS pump hoses, feed hoses, or the steering rack (took the cover off to check). No signs of leaks on any of the underside, nor on the floor where the car is parked....

Kein_Ersatz

Me likes a good mystery - subscribe

Mike J

consumption over the last day or so - zero.

So it must be a slow leak.

We will keep chasing it, but i might take a while...

Cheers

Mike

ronnie993tt

Must be Pentosin thief. Isn't it around $50 a litre?

Quadcammer

nah, like $30 but still

Knight

Great of Mike to post this up for me, yep somehow Pentosin is mysteriously missing.

And yes it's like stupid expensive up here in Canada!

So far no consumption at all.

ronnie993tt

Yup $50 here. That's why we shop for everything stateside.

wagongotya

leaks at the pump or the steering rack

Mike J

Nope, sorry. Its a drain on the low pressure side of the clutch assist circuit - impossible to drain that from the high pressure side.