Clutch Master Cylinder and Slave Cylinder issues, grinding gears

[AndyBees]

I suspect this topic has been hashed and rehashed. So, I apologize for not spending hours trying to find a few suggestions for my problem. I'm running out of time due to a scheduled road trip departure date coming up. Still have lots of things to do.

Anyway, while doing all kinds of maintenance on the Van, I discovered that the Clutch Slave was leaking fluid, very minor. So, why not? I replaced the Slave. (And, I replaced both rear wheel cylinders due to one of them becoming slightly wet with fluid after installing brake shoes.)

So, along with the brakes, using a Power Bleeder, I bleed both systems using well over a quart of fluid.

The problem is that the Clutch Pedal has to be pushed hard to the floor to change gears without grinding. So, this morning I re-bled the Clutch System resulting in perfect shifting (there was some air in the system). Then I drove the Van into town to run a few errands and now it's doing the same thing.

(I never let the fluid in the reservoir get below minimum.)

New braided brake hoses 4 years ago and the brake and clutch lines are not rusty.

Is this a Clutch Master Cylinder Issue?
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[Zeitgeist 13]

How much slop is there in your clutch pedal? If there's a lot, it might need to come out and be welded up at the clevis pin attachment point.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Vanagon Nut]

[AndyBees]

Clutch slop seems minimum. I do plan to remove the dash Monday or Tuesday to access the pivot pin/bushing on the brake as it seems to be binding a bit, even with an extra spring. So, while in there I can check the clutch pedal pivot as well.

This has all happened after a new pressure plate, clutch disc, TDI pilot shaft and re-installing my modded DK tranny last week. I took it out last October for the pilot shaft but just got back to it recently. The old "unknown mileage" tranny worked fine for the last 6 months.

I did bled the Clutch hydraulics again but haven't tested it. Seems there is no fluid loss anywhere because the level stays the same, at the max point.
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[windnsea]

Some replacement clutch slave cylinders have a shorter pushrod and will not fully depress the clutch. I found this out when I replaced mine. I was fortunate to catch it before installing it. I simply switched in the older and longer pushrod and all went well.

[Gnarlodious]

You may have residual air bubbles in your hydraulic lines. It may seem normal when driving in the morning, but in midday heat in city traffic the bubbles can expand and cause the problem you describe. It may take a few tries to get all the air out.
_________________
Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[Vanagon Nut]

[AndyBees]

Well, I got the same results with this last bleeding of the Clutch Hydraulics.

It worked fine for about 10 or 12 shifts and then began to require a solid press on the pedal all the way to the floor to keep the gears from grinding, especially reverse!

Okay, it will be Monday before I can get back to this clutch hydraulics issue. I've got a 12 hour round trip tomorrow to go fetch a craigslist buy south of Chattanooga, TN.
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[windnsea]

Don't forget that the clutch master cylinder 'fills from the top and pushes the fluid to the bottom and then out to the slave cylinder, where it fills from the bottom and any air 'in the slave cylinder' can be bled through the bleed valve.

If there is air in the master you need to reverse bleed to get it out.

Someone had posted (and I can verify that this is very cool and works) the following:

Attach a clear plastic bleed hose to the bleed nipple on the left rear brake wheel cylinder, long enough to reach over to the clutch slave cylinder. Start to pump the brakes slowly until the hose has no air into it. Pop it over the clutch slave cylinder bleed fitting and slowly open it. Now, while watching the brake fluid reservoir, slowly pump the brake pedal (with handbrake off) and watch for air bubbles. If they start to appear coming into the reservoir, then there was air in the clutch master cylinder which could not be removed with a pressure bleeding. Slowly pump about 20-30 times and then close off the bleed valves on the clutch slave cylinder and the left rear wheel brake cylinder, remove the plastic line, and take it for a drive.

I did this to mine when replacing a clutch master cylinder and it really works! I hope this will cure your problem.

windnsea

[AndyBees]

WindnSea, I do believe you are onto something. (Thanks for the info.)

I unintentionally forgot one fact. After I put all the electrical stuff back together and turned the ignition on, the Brake light (in the TDI Cluster) was ON. I searched the wiring for almost two hours trying to figure out why that light was ON. Well, it was on due to the "transplanted" bells and whistles I did, red BRAKE light means, low fluid, duh!

As I did the brake work, I broke each bleeder loose and retightened for the flush I planned to do later. Also, I let fluid flow through the two new rear wheel cylinders as I installed them, thus more fluid loss. And, when I was re-installing the transmission was when I noticed the old Clutch Slave was leaking a bit of fluid.

So, all the fluid loose added together resulted in the low fluid light coming on and no doubt most likely allowed bubbles to get in the Clutch Master Cylinder.

Okay, I will do the reverse bled late tomorrow afternoon.

I'm totally exhausted. I just got back from a 500 mile round trip to North Georgia towing a truck on a dual wheel trailer pulled by my Dodge with the 5.9 Cummins. Wow, and I had a blow-out on one of the trailer tires on the return trip. What should have been 9 hours ended up being 17 hours .....
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[AndyBees]

Well, I finally got a chance to get a hose to "back flush" the clutch hydraulic system to get the air out of the Clutch Master Cylinder.

A 3/16 inch inside diameter clear hose from your local hardware fits both bleeder valves nice and snug. I got 4 feet. Using clear hose allows observation to flush out air before connecting to the Clutch Slave from the Brake Cylinder. I suspect the clear plastic will only be good for one service as the brake fluid will most likely soften it.

I'll report back on the results.
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[Gnarlodious]

The clear vinyl hose is stable with brake fluid. I have had it feeding my MC for years.
_________________
Vanagon ’83 diesel AAZ w/Giles injection, 5spd 4.57R&P+TBD and a '78 diesel Rabbit

[AndyBees]

Well, so far so good! Shifting is awesome.

I highly recommend this method of getting air out of the Clutch Hydraulic System. It's a bit messy but gets the job done.

For reference, this is how I did it.

1. Top off the brake fluid reservoir first thing, if necessary.

2. Loosen the left rear brake bleeder valve and then finger tighten.

3. Loosen the bleeder valve on the clutch sleeve and then finger tighten.

4. Press the 3/16 inch clear plastic hose onto the brake bleeder valve (I used just under 4 feet of hose).

5. Next loosen the brake bleeder valve and allow the clear hose to fill with fluid pushing out all air ..... I used a clear empty water bottle to catch the fluid.

6. Once the hose was full with no air bubbles, I loosened the clutch slave bleeder valve and allowed it to free flow fluid and then pushed the hose down on it.

7. I placed old newspapers under the transmission and wheel to soak up brake fluid that will drain out around the threads of the bleeders.

8. Next, I pumped the brake pedal using a series of 3 slow downs and ups. After each series, I checked to make sure there was no air in the clear hose.

9. Just to be sure, I did 10 of the 3 brake stroke series.

10. I finished by closing the Clutch Slave Bleeder first and removing the hose. While the hose free flowed brake fluid, I closed the brake bleeder valve.

Then, I filled the brake fluid reservoir to the maximum level.
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[windnsea]

Windnsea here

Glad that the shifting is going well. When I first read about this way to bleed the clutch system, it seemed crazy, but then a little light went on in my head, so I tried it! Worked well!

Glad that I could be of help. Btw, my '83 1/3 is the same color combination as yours. I got one of the first waterboxers to come into the country and was lucky to get one with a sunroof! Still going strong with 330,000 miles on it!

windnsea

[AndyBees]

[MarkWard]

I used to have a old fashioned oil can just for back bleeding brake fluid. I would fill the oil can with brake fluid open the bleeder valve and pump fluid into the system using the oil can. It worked quite well. I like the idea of using the brake hydraulics to back bleed the clutch hydraulics. Clever.

Andy, good luck on the trip. I just ordered upgraded clutch parts and purchased the input shaft from Christopher at T3. Hope it all goes well. mark
_________________
☮️

[dobryan]

That is a clever technique. Can be very useful for someone who did not bench bleed a new master cylinder as well.
_________________
Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794

[AndyBees]

[AndyBees]

This is a follow-up!

Long story short ........ the damn new ATE Clutch Slave Cylinder was junk!

Late yesterday afternoon, I had to re-install the old Slave Cylinder. Due to our planned Alaska Road trip departure being this morning at 8:00 am, I had no other choice.

The old slave cylinder is working just fine. I'll keep an eye on the fluid level!
_________________
'84 Vanagon Tin-top, ALH TDI. 1989 Tin-top
1983 Air-cool, 225k miles, 180k miles mine. Seven trips to Alaska from 1986 thru 2003.

[dobryan]

Great! Enjoy the trip...
_________________
Dave O
'87 Westy w/ 2002 Subaru EJ25 and Peloquin TBD

"To travel hopefully is a better thing than to arrive." Robert Louis Stevenson

MD>Canada>AK>WA>OR>CA>AZ>UT>WY>SD
https://www.thesamba.com/vw/forum/viewtopic.php?t=620646

Building a bus for travel in Europe (euroBus)
https://www.thesamba.com/vw/forum/viewtopic.php?t=695371

The Western Syncro build
https://www.thesamba.com/vw/forum/viewtopic.php?t=746794