MB 616 diesel powered Astro build - Page 7 - PeachParts Mercedes-Benz Forum

JB3 · #91 06-12-2013, 09:25 AM

Quote:

Originally Posted by JB3

small update-

So the first thing I did to try and get the clutch was move the bolt for the master to the pedal into the lower of the two holes on the pedal and get that much further swing. That did nothing, with the engine running I could not get it into gear.

Then looking over the clutch system, I remembered that the push rod for the GM slave is actually a separate piece, a little steel dowel, and why not just put in a longer push rod for the same result?

I pulled out the stock pushrod that came with the slave, which is about 4.5 inches, and have been making progressively longer pushrods by 1/4 inch increments.

4.75 inches got me an ominous click and no gears with the pedal depressed
5.00 inches got rid of the ominous click, but still no gears
5.25 inches got me able to get it into 3rd and 4th if you work at it, and no other gears
5.50 inches got me much easier into 3rd and 4th, and as hard as 5.25 into 1st and 2nd, but no 5th, and no reverse. In those gears clutch engagement seems decent.

so this turned out to be barking up the wrong tree, the hydraulic system will compensate some for different length pushrods evidently every time you rebleed it, and i was not getting anywhere. The longer pushrods seemed to reduce the volume of stroke need to move the clutch in the slave by moving the piston back, but not enough to actually get it reliable into gear.
I ended up also increasing the throw of the master via lowering the pivot attachment point on the clutch pedal, and still no reliable clutch with any of the pushrod lengths, though tantalizingly close.

Basically there are too many questionable variables to be absolutely sure whats preventing me putting it in gear. There is the custom flywheel, the mount point for the pivot for the clutch pedal possibly preventing a full master stroke, the possibility of the slave not having enough stroke with non stock parts in the bellhousing, ect ect.

Ive decided to go back to a totally aftermarket floor mounted clutch pedal and large master cylinder with a 3/4 inch bore and a 1-3/32 stroke to eliminate all questions on the pedal end. According to the manufacturer, this should work with an S-10 slave and is actually a little on the large side to match, and the astro specific slave I have is the same slave, just different mounting ears. If It turns out I need a longer stroked slave, I can still use the same master.

The large body lift will make it possible for me to mount this floor unit a little below floor height to match generally the brake and gas pedal foot pad heights.

This is the first time ive tried to match non stock hydraulic components like this, so if anyone has any advice or experience, id welcome their input!

ROLLGUY · #92 06-12-2013, 12:26 PM

Quote:

Originally Posted by JB3

This is the first time ive tried to match non stock hydraulic components like this, so if anyone has any advice or experience, id welcome their input!

I will offer my experience with my neighbors Ford Escort. He hired me to put in a new clutch because it was worn so bad, the engine would rev in all gears higher than 4th. I replaced everything with new parts (flywheel, pressure plate, disc, pilot bearing) sourced from Amazon (my neighbor likes Amazon). After removing and reinstalling the trans THREE times to check for different potential problems, I still could not get the clutch to disengage without grinding the gears. We even replaced the entire hydraulic system with new parts, and still the same problem. The experts (including me at first) suggested it had to be the pilot bearing too tight to the input shaft. After the first time R&Ring the trans, the bearing was checked and was found to be fine. The second time, the clutch and pressure plate were replaced with new (again). The third time we double checked everything and still could not find the problem. This all happened about three months ago, and the car still sits with no idea as to how to fix it. However, I suspect you may be having a similar problem with yours. The thing I did not check was how tight the disc fit on the splines of the input shaft before installing the clutch. The alignment tool fit perfectly in the clutch, but thinking back, it was a little hard to pull the trans tight to the engine for the last one inch or so. I am half tempted to hole saw a hole in the bottom of the bell housing to see if the disc is freely moving on the input shaft while someone depresses the clutch. You may have the same problem. You could have a problem with your pilot shaft bearing as well, as yours is not a stock application. I would first try (with help and the rear on stands with the parking brake on) to test if the clutch is or is not disengaging manually (actuating the clutch fork with a lever), thereby eliminating the hydraulic system from the test. This will tell you if mechanically the clutch is working properly, and you can rule out or look to an input shaft problem (splines or input shaft bearing/bushing too tight).
This test was performed on the Escort, as we thought the fork might have been bent, causing less than adequate disengagement....Rich

JB3 · #93 06-12-2013, 01:04 PM

Quote:

Originally Posted by ROLLGUY

I will offer my experience with my neighbors Ford Escort. He hired me to put in a new clutch because it was worn so bad, the engine would rev in all gears higher than 4th. I replaced everything with new parts (flywheel, pressure plate, disc, pilot bearing) sourced from Amazon (my neighbor likes Amazon). After removing and reinstalling the trans THREE times to check for different potential problems, I still could not get the clutch to disengage without grinding the gears. We even replaced the entire hydraulic system with new parts, and still the same problem. The experts (including me at first) suggested it had to be the pilot bearing too tight to the input shaft. After the first time R&Ring the trans, the bearing was checked and was found to be fine. The second time, the clutch and pressure plate were replaced with new (again). The third time we double checked everything and still could not find the problem. This all happened about three months ago, and the car still sits with no idea as to how to fix it. However, I suspect you may be having a similar problem with yours. The thing I did not check was how tight the disc fit on the splines of the input shaft before installing the clutch. The alignment tool fit perfectly in the clutch, but thinking back, it was a little hard to pull the trans tight to the engine for the last one inch or so. I am half tempted to hole saw a hole in the bottom of the bell housing to see if the disc is freely moving on the input shaft while someone depresses the clutch. You may have the same problem. You could have a problem with your pilot shaft bearing as well, as yours is not a stock application. I would first try (with help and the rear on stands with the parking brake on) to test if the clutch is or is not disengaging manually (actuating the clutch fork with a lever), thereby eliminating the hydraulic system from the test. This will tell you if mechanically the clutch is working properly, and you can rule out or look to an input shaft problem (splines or input shaft bearing/bushing too tight).
This test was performed on the Escort, as we thought the fork might have been bent, causing less than adequate disengagement....Rich

Interesting, I tried an experiment of putting it in gear and starting it, and I can get it to roll doing that and it feels normal. This was when I had it as close as I got with the bled hydraulics, where with the clutch depressed it wouldnt move, but I could not shift it.

However in gear, letting out the clutch and giving it gas it moved pretty normally, so im thinking that the issue is still external of the bellhousing, but I may be forced to take down the transmission if my new pedal apparatus does not produce any results.

funola · #94 06-12-2013, 01:07 PM

Being able to see what's going on inside the bell housing will help tremendously. Instead of a hole saw, a usb borrscope / laptop and a 1/2 inch strategically drilled hole will end up with smaller hole.

JB3 · #95 06-12-2013, 01:32 PM

Quote:

Originally Posted by funola

Being able to see what's going on inside the bell housing will help tremendously. Instead of a hole saw, a usb borrscope / laptop and a 1/2 inch strategically drilled hole will end up with smaller hole.

with the lever boot removed, there is a pretty large window into the bell, as seen here- I need to get someone to depress the clutch when I am under to really see whats happening. However, you can actually see from above through the hatch, but not as well. I can definitely see the slave activating though
(please ignore the temp wiring!)

you can also see the slave pushrod, here are a bunch of different ones I made to test lengths. The one that came with the slave is bottom

here was one of the schemes for extending the master stroke. In this pic you can see at the red arrow how far the master would depress with the pedal to the floor

So I lowered the pivot and made a bracket that bolted to a welded part on the master pushrod itself, this depressed the master completely to the red line marked here, though the pivot can really be a little higher than this as it reduced pedal movement to about half. Unfortunately where the red bracketing is pointing is a bend around the fuse box area, so no pivot could go there unless built out at an angle, which i suppose is a possibility.
Unfortunately though, im guessing every time I do anything to this pedal, better to start with a complete unit that comes as a tested package

funola · #96 06-12-2013, 01:44 PM

If you have an opening already and no helper, rig up some lighting, ruler and cell phone camcorder to see what it's doing.

ROLLGUY · #97 06-12-2013, 02:17 PM

Quote:

Originally Posted by JB3

Interesting, I tried an experiment of putting it in gear and starting it, and I can get it to roll doing that and it feels normal. This was when I had it as close as I got with the bled hydraulics, where with the clutch depressed it wouldnt move, but I could not shift it.

That tells me that your hydraulics are in fact mechanically engaging/disengaging the clutch, but there is a drag, and something causing the disc to still turn with the engine. This is still the same problem with my neighbors Escort. The Escort can be put in gear, started, and driven normally except for shifting. It will grind if tried to put in any gear with the engine running. It is just like shifting without the clutch, getting the right RPMs to shift without grinding (clutch in or out, makes no difference). With the escort, the engagement point feels exactly in the same place as it should be (once started in gear). It is also the same before and after replacing the master and slave (I told my neighbor it was a waste of money, but he wanted to rule out the hydraulics completely). I believe your Astro and the Escort have the exact same problem. How to fix it, I don't know. My neighbor paid me two of the three times I worked on his car, the third he has yet to pay me for. I am sure he will pay me the next time, IF I actually am able to find the problem. You may actually end up being a great help for helping find the problem with the Escort. By the way, can anyone tell me why they named the car Escort?

JB3 · #98 06-12-2013, 03:57 PM

Quote:

Originally Posted by ROLLGUY

That tells me that your hydraulics are in fact mechanically engaging/disengaging the clutch, but there is a drag, and something causing the disc to still turn with the engine. This is still the same problem with my neighbors Escort. The Escort can be put in gear, started, and driven normally except for shifting. It will grind if tried to put in any gear with the engine running. It is just like shifting without the clutch, getting the right RPMs to shift without grinding (clutch in or out, makes no difference). With the escort, the engagement point feels exactly in the same place as it should be (once started in gear). It is also the same before and after replacing the master and slave (I told my neighbor it was a waste of money, but he wanted to rule out the hydraulics completely). I believe your Astro and the Escort have the exact same problem. How to fix it, I don't know. My neighbor paid me two of the three times I worked on his car, the third he has yet to pay me for. I am sure he will pay me the next time, IF I actually am able to find the problem. You may actually end up being a great help for helping find the problem with the Escort. By the way, can anyone tell me why they named the car Escort?

im wondering if both issues are related to a too thin release bearing, for both our cars. did you replace the release bearing as well when you went back in?

looking at this pic, doesn't it seem like the release lever is pretty far to the rear of the opening? almost like the slave is actually engaged, not at rest?

this is what that release fork looks like on the inside, and below the custom flywheel-

my new theory for my situation is because of this adapter kit, custom flywheel, ect, that the stock release bearing is too thin, so no matter how efficient the hydraulics, the arm at rest is just too far back to really disengage the clutch. It just seems wrong in the above pic, like if it were 3 inches further to the left, that would be the right place to sit.

ROLLGUY · #99 06-12-2013, 04:18 PM

You and I are dealing with two different situations, in that your application is custom, mine (Escort) is stock. You may in fact have a too short release bearing, thereby not disengaging the clutch even at maximum fork travel. I am planning to holesaw a hole (about 1" dia.) in the bottom of the bell on the Escort to actually see the gap (if any) between the disc and the flywheel/pressure plate. By having someone push the clutch pedal, I would be able to easily see or feel any gap. If the disc feels solid against the flywheel, I will know that the splines are too tight. On your application (having drilled a hole), you would be able to see if in fact the clutch fork is traveling far enough to disengage the clutch. After this test is performed, a simple rubber or plastic plug will fill the hole (a proper size plug sourced before drilling the hole)......Rich

panZZer · #**100** 06-12-2013, 04:40 PM

Quote:

Originally Posted by JB3

im wondering if both issues are related to a too thin pilot bearing, for both our cars. did you replace the release bearing as well when you went back in?

looking at this pic, doesn't it seem like the release lever is pretty far to the rear of the opening? almost like the slave is actually engaged, not at rest?

this is what that release fork looks like on the inside, and below the custom flywheel-

my new theory for my situation is because of this adapter kit, custom flywheel, ect, that the stock release bearing is too thin, so no matter how efficient the hydraulics, the arm at rest is just too far back to really disengage the clutch. It just seems wrong in the above pic, like if it were 3 inches further to the left, that would be the right place to sit.

yup its a TB depth issue, a v5 camaro has a two line one thats direct juced, i wouldn/t have used theis slave /arm setup. BUT an adjustable arm pivot ballstud could be the cheapest fix with this setup.
the aftermarket ones are all at least $150.00
Tilton 61-612 Tilton Hydraulic Throwout Bearing Kit
here is a different one like your type --you could hack the bracket cast into the bell off and go with this type.
New Clutch Setup or Done with the Mcleod Hydraulic Throwout Bearing HTOB « Leons MGB V8 Special.
others some with spacers like

http://www.ebay.com/itm/New-GM-T-5-Stock-Clutch-Hydraulic-Throwout-Bearing-/380645806127?pt=Motors_Car_Truck_Parts_Accessories&hash=item58a042102f&vxp=mtr#ht_2458wt_766

chevy t5 hydraulic throwout bearing - Bing Images
Stephen Blackburn's 1971 MGB with Chevy 283cid V8

ROLLGUY · #**101** 06-12-2013, 04:51 PM

Quote:

Originally Posted by panZZer

yup its a TB depth issue, a v5 camaro has a two line one thats direct juced, i wouldn/t have used theis slave /arm setup. BUT an adjustable arm pivot ballstud could be the cheapest fix with this setup.
the aftermarket ones are all at least $150.00
Tilton 61-612 Tilton Hydraulic Throwout Bearing Kit
here is a different one like your type --you could hack the bracket cast into the bell off and go with this type.
New Clutch Setup or Done with the Mcleod Hydraulic Throwout Bearing HTOB « Leons MGB V8 Special.
others some with spacers like

chevy t5 hydraulic throwout bearing - Bing Images
Stephen Blackburn's 1971 MGB with Chevy 283cid V8

I have heard all kinds of bad things about hydraulic throwout bearings, Jeep in particular. I for one would never use one. The simple bearing and fork is tried and true. Although this is not a 4X4 application, removing a TC and trans to get at a faulty hydraulic TB would be a real pain. Just my opinion though, everyone is free to do as they please....Rich

JB3 · #**102** 06-12-2013, 05:04 PM

Quote:

Originally Posted by panZZer

yup its a TB depth issue, a v5 camaro has a two line one thats direct juced, i wouldn/t have used theis slave /arm setup. BUT an adjustable arm pivot ballstud could be the cheapest fix with this setup.
the aftermarket ones are all at least $150.00
Tilton 61-612 Tilton Hydraulic Throwout Bearing Kit
here is a different one like your type --you could hack the bracket cast into the bell off and go with this type.
New Clutch Setup or Done with the Mcleod Hydraulic Throwout Bearing HTOB « Leons MGB V8 Special.
others some with spacers like

chevy t5 hydraulic throwout bearing - Bing Images
Stephen Blackburn's 1971 MGB with Chevy 283cid V8

ive been researching an internal slave related to above, downside is if it ever leaks, im having to remove the transmisison.

here are the parts that came off a 1990 AstroRS

bell housing
clutch release lever

here are the parts that were ordered for a 1990 AstroRS

master cylinder
slave cylinder
release bearing
clutch kit

here are the parts that were installed from a 1990-91 S-10

gearbox- 1352-201 T-5 non WC, gear ratios- R-3.76 1-4.03 2-2.37 3-1.49 4-1.00 5-0.86

Crossover part numbers are the master cylinder for the 1990 RS van are the same with the 1990 K1500 full size truck, the slave looks identical but for bolt pattern and bleed location to a 1990 S10 as well.

Interestingly related to the K1500 is that in 1990 there were two options, and internal and external slave, so maybe I could use either in this application, though id prefer an external slave

panZZer · #**103** 06-12-2013, 05:07 PM

Quote:

Originally Posted by ROLLGUY

I have heard all kinds of bad things about hydraulic throwout bearings, Jeep in particular. I for one would never use one. The simple bearing and fork is tried and true. Although this is not a 4X4 application, removing a TC and trans to get at a faulty hydraulic TB would be a real pain. Just my opinion though, everyone is free to do as they please....Rich

and just as simple --a cable actuated TH bearing, like 70s gm small cars and 90's mustangs.

i believe this one actuated a T5 in a vega chevy monza etc

clutch cable -honda -kawasaki -yamaha -suzuki -harley -sportster in eBay Motors | eBay

KarTek · #**104** 06-12-2013, 08:27 PM

Yours is the same problem that I just dealt with on my Corvette. I replaced the clutch master and slave and could not for the life of me get it to go into gear. I bled it literally for hours and ran about a half a gallon of fluid through it.

What I learned was that you have to remove the slave cylinder from the mount and hold it vertical and twist it around in different directions so that the bleeder is upside down then right side up, etc... The idea is to make sure trapped bubbles migrate to the hose. Then, you take your finger or a screwdriver and push the piston all the way in until it stops.

Now, press the pedal and pump it gently until the piston moves all the way out. Take care not to blow it out the end of the cylinder if there's no retaining ring. Then, repeat the process: turn it over and over, push it in then pump it out.

Do this a few times and then re mount the cylinder and see what it does.

mach4 · #**105** 06-12-2013, 09:55 PM

I think you need a helper to be able to monitor what's going on while someone pushes down on the clutch. Air in the line would seem to produce the kinds of symptoms you're seeing.

I also like the idea of a cable operated clutch... at least for troubleshooting. That way you'd know exactly what you're dealing with and determine if the problem is the actuating piece or something internal.

Good luck.