Mk9 question

This is a new car to me (Z10C) and my first time opening one of these up, so maybe this isn't a problem. I cracked open the rear cover and it looks like it's stuck in a low gear because the middle selector is pushed in. I couldn't put it in any gear beforehand, so this would explain that. Although the shifter does move laterally like it's in neutral, not in a gear. Does that make sense? I know I need to push in the other two selectors to continue the disassembly, but this middle one is supposed to be out, right? How do I get it out? Help!

http://i188.photobucket.com/albums/z...04/hewland.jpg

what happens if you turn the top nut? did you try to pry it witha small pry bar? usually i get the nuts off the the middle fork out and the two outers in.

Shifting MUST be done without any problems. All the play you have when you move the shift handle left to right so you thought that was in neutral tells me you have not worn but "shot" u-joints on your shifting rod. My guess is there is so much slop that the shift finger got out of position during a shift. Use good u-joints and cover them with shrink tubing. To disassemble the gear box move the top and bottom shift rods forward. First pull the center shift rod back using a small pry bar or even a screw driver, it should not take much effort to pull it back.

There is no problem looking at the picture, other then the joints probably are worn badly. The shift finger is in the correct place for it to be in first gear, you might have needed to rock the car to get it in neutral. Use a screw driver to move the selector away from the bearing carrier to get the shift fork to the neutral position. Then follow the instructions on the hewland website to complete the gear change. Note that you will need to lock the box in 2 gears to remove and/or tighten the 2 big nuts. Do this by manually pushing the reverse shift fork forward, placing it in reverse, and then pushing the 3-4 fork forward placing it in 3rd gear as well. You might need to rotate the layshaft to accomplish the second gear engagement. You will also have to do this to tighten the nuts upon reassembly, just be sure to put everything back in neutral before covering it up. I double. Heck that all the gears engage before installing the rear cover and that assures that it is not left locked up.
John
PS you do not need to run that expensive green stuff, mobil 1 75-90 available from most all auto parts stores will work fine. 1 quart after gear change and 1.5 from dry. These specs are on the hewland site as well, and can be found on Taylors site.

Call Wehrmann Engineering in Haupauge NY. Mark (Wehrmann) is a very good guy and specializes in this stuff. If you can fix it he'll very likely help you figure it out and if you can't, he can.

I hadn't tried prying it out because I didn't want to hurt anything, but I just did and it popped out with a little persuasion from a screwdriver. So that's good, but now I can't get the two outer selectors pushed in. I tried pushing with my fingers as hard as I could and I tried with the shifter and clutch from the cockpit but neither worked. Am I missing a trick? A friend stopped by (no FF experience, but a big car nut who knows his way around a shop) and said that hydraulic clutches need the engine on to build up pressure on the clutch so they can work. Doesn't sound right to me, but I'm clearly no expert.

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Originally Posted by syrarch04

.... said that hydraulic clutches need the engine on to build up pressure on the clutch so they can work. Doesn't sound right to me, but I'm clearly no expert.

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And YOU are right. The hydraulic clutch has a 'master cylinder' that's actuated by the clutch pedal. That puts fluid pressure in to the line which in turn actuates the 'slave cylinder' to move the throw out bearing. There is NO hydraulic pressure pump involved (like a power brake system).

The two gear shift rods 'should' move in fairly easily. If not try rotating BOTH rear wheels in the same direction a little.

EDIT: Posted before I read the above two posts.

I can't tell from the photo but the selector finger can get really worn. I had one that was so old and worn that is was making shifting very difficult. I still have it hanging in my workshop. Take a look at where it actually selects the gears. Is it all rounded? Has it worn down to a narrow finger? If it's really worn down it could fit through all 3 selector rods like it was in neutral. If so, that's as bad as it gets. Here's what it looks like brand new:http://s2.pegasusautoracing.com/bigp...asp?RecID=8662

That might not be the problem but it's worth checking into.

You should be able to pull the center selector rod (1st/2nd gears) back, but even if it's OK it could take some leverage beyond just your fingers. If it is actually stuck, then there's obviously a problem. There are a lot of resources out there for you if you need. I've tried both Taylor Racing and Keith Averill.

Try rocking the car back and forth while pushing the shifter gates forward to lock them in position. It may take moderate pressure with your thumb to make them move into the new position.

Also remember the threads on the shaft nuts are one right hand thread and one left hand thread.

I just went through this with my car for the first time in 12 years so I had forgotten what it normally feels like. Once you see how the box works and how everything has to line up correctly between dog rings and gears you will see why it is "normal" to have to rotate both axles to allow gears to engage. Just wait until you try to reassemble the box the first time. Patience and lots of thinking about what needs to happen regarding lining parts up correctly will be necessary. The guys that do this all the time probably can do it in their sleep. For first timers and others who do it rarely it just takes trial and "non destructive" error. Not to worry. Just don't be in a hurry. :)

Dick
CM85

With some of the race weekends I've had over the early years in my racing, I'm pretty sure I have done this in my sleep. ;)

FYI regarding Jim Garry's reference to a new selector. Taylor and other's make modifications that will make the finger look different from a "stock" new part. My Taylor part doesn't look "worn" just machined differently. I don't have a picture.

Dick

Quote:

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Originally Posted by Northwind

With some of the race weekends I've had over the early years in my racing, I'm pretty sure I have done this in my sleep. ;)

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You win. I knew someone would say that!:)

Dick

Whan I change gears on a Hewland, I like to have the vehicle on the floor, so when I need to engage a gear (or two to remove the large nuts), I can rock it back and forth. Moving the rods in and out of gear are a lot easier that way. And when assembling the carrier after a gear change, it's easier to get it to move forward, that last "litle bit" that it takes to finish the job.
I'm here often, if in doubt, call.

The normal amount of force needed to move the shift rods by pushing on them is around 20 lbs, so moderate force, not light but not too heavy. If one won't move you just have the dogs lined up face to face, so just move something. You can sometimes just rotate one of the shafts, or an axle. There are interlocks so adjacent shafts cannot be put in gear at the same time, which is why you need to lock up the box by putting it in reverse and third at the same time - outer two shafts both in.

Brian

From your discription, it sounds like your shift linkage is broken or if lucky missing a linkage thru bolt....."won't shift into any gear and when u take the back cover off, it is actually in 1st.....and in first, the shift lever is very movable like nuetral........that is, if you couldn't select any gear before the cover was off.....cover off, obviously selector not doing anything but going thru slots, spinning out past where the cover was.....my 2 cents

Syrarcho4

If you could push the two outer rails in ....it would be very bad. The inter-locks between the rail are stopping them from moving.
With a small pry bar , gut under the shift rail head and pop it back into the neutral position.
Then you will be able to push in the two outer rails to double gear it and un-torque the layshaft and pinion shaft nut.

If you need any help, Please call me anytime , or shoot me an e-mail. I answer e-mails all night..


scotty
scotty@taylor-race.com
800-922-4327

Quote:

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Originally Posted by Brian

..... There are interlocks so adjacent shafts cannot be put in gear at the same time......Brian

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And THAT is a very GOOD thing. About our 4th weekend with the Reynard, Jeff brought it off brack with it 'locked' in 3rd gear and he couldn't select neutral or any other gear. GOOD THING!

Opened up the box and indeed it was in 3rd gear but, the SELECTOR FINGER was over in the 1st/2nd shift rod fork>>>>> EEIKS!

If he had managed to put it into 1st or 2nd on track... well....

Don't ask me how it happened. I have no clue. Fixed it and it never happened again.

If I remember correctly, we had the same thing happen. I think I sourced it to the nut holding the shift fork was coming loose and allowed the shift fork to rotate its position on the fork shaft. This slop allows the shift gates to sepparate a bit and allow the shift finger to find the next gate without disengaging the previous gear. Oh the memories of the mk-9 days.

The reason that happens is a worn shift fork that can slip between the selector fingers as the gears are in the process of being engaged. I've had it happen too..

Brian

The normal reason a selector finger ends up in one gate while the box is in another, has to do with the selector rod of the gear it was stuck in.
If the detent pressure is too light and the rod(and attached fork) doesn't stop in neutral, the rod can continue to travel, or fall back into gear, regardless that the shift finger has left to engage another gear(rod). Because the lockout detent between the different rods (1-2, 3-4 and Rev on Mk series) keeps you from moving into the new gear, the other rod is still in control of gear selection.
I've seen this happen with new shift fingers and shift rod/fork combinations that were not loose (thus no gaps for the finger to fall through). The shift finger would need to be extremely worn-thin to do it the other way, and should have been replaced years before.

Download a copy of the hewland service manual for your gearbox. It should be easy to find. This will provide you with proper torque specs among other things.

The only thing that I found it does not point out is that in order to remove the 4th gear from the carrier, you will need to pull the bushing and bearings from it, otherwise it will not clear the fork.

Personally, I found the car easiest to work on in the air, with the nose lower than the tail. This way, you can manually rotate the driveshaft(s) during final installation in order to get the pinion shaft splines to line up, and the trickle of fluid will be minimized allowing for a proper application of hylomar.

Keith - thanks for that, it helps explain things for me.

Brian

So I pulled everything apart and reassembled and it actually went pretty smooth. Even that last 1/2" only took about ten seconds to get in. Maybe I'm just lucky.:D The selector buttons are still very tough to move in and out. They do move but it takes a lot of pressure, mostly way more than I would expect. Is this possibly just because it sat for 8+ years? The more I work them, they seem to move a little better. Is it cool to squirt some WD40 or something similar on them? I don't want to add anything to the mix that may have a negative effect on the gear oil (redline). For what it's worth, when they can be persuaded to move it is a smooth movement, and nothing feels crunchy or broken and all three resist similarly. Suggestions?

See "we" all said you could do it!

When I did mine after letting the gears and shafts drain for a day or two the shifting was stiff with the shifter until I ran the engine and allowed the gear oil (Redline Shockproof) to circulate. Previous gear oil was probably Valvoline synthetic. The car was supported securely on 6 by 6 timbers so I could run through the gears in the normal manner (using the clutch).

Dick

With the leverage of the shifter you shouldn't have much of a problem....just pushing on those back selectors can be a pain and can cut your fingers....by the way, if you fool with the detent springs on the outside to freeup the shafts, WATCH IT!, I losened mine once and it downshifted from 4th to third by itself from the weight of the shift linkage and heavy end of straight braking, did it a couple of times before I figured it out.....not good to find youself in 3rd asking, I know I went to 4th, what was that, how come I'm still in third.....basically rev city........just a warning

Quote:

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Originally Posted by syrarch04

The selector buttons are still very tough to move in and out. They do move but it takes a lot of pressure, mostly way more than I would expect. Is this possibly just because it sat for 8+ years?

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Mine are fairly tough to push in and out. I often need some leverage in the form of a flat piece of metal. If I had really strong fingers, it would no doubt be easier.:)

The selector shafts are indeed hard to move with just your fingers when you're sitting behind the car. That's normal. It'll feel just fine when you're in the cockpit flicking the shift lever. You'll have a lot of mechanical leverage (and the red mist) helping you.

Lots of useful stuff in here. I'm curious about detents - how do I know if I have too little/enough/too much detent pressure?

Thanks,
Gary

Gary,

Every builder will have what they feel is the right pressure .You will want around 18 pounds. Anything less can be bad . If you have too little detant pressure than the rail can go into neutral position under hard breaking. Remember you will have alot of leverage in the shifter lever.
Your main goal is a nice crisp snap when it goes into gear. We spend a very long time on detent pressures so that every shift feels the same. You do not want to have push like hell to get into 2nd...and then just bearly touch it for 3rd....they should all feel the same.

scotty
scotty@taylor-race.com

Awesome, thanks Scott.

It's my first time working on the forks, so it's definitely a learning experience.

Your welcome Gary..

Maybe this will help you too..

http://www.taylor-race.com/pdf/MK9numbers.pdf


scotty