R21 Gearbox setup Ideas ?

[Howard Jones]

I have a GTD and I'm about ready to start Her up but the gearbox seams to be in gear. I have tried rocking the car, attemped to shift to neutral Etc. I would like to start it up for the first time out of gear, so I don't have to hold the clutch in and start it. Someone has to hold the fire bottle, mess with the carb, timing etc.
Any ideas?

[ January 05, 2003: Message edited by: Howard Jones ]

 

Put that bad boy on 4 stands and get to firing it up. Deal with that tranny later.
The purr of the engine just may spark the idea of how to shift the transmission.
Have fun I wish I was ready to fire up mine.
John

 

[Robert Logan]

Howard,

It would not suprise me to hear that the clutch is stuck on.

There are two ways to fix it, take apart or start the car with the clutch pedal in and let her go !!!!

I will let you decide the correct way ?????

Best wishes,

Robert

 

[Scott]

As a safety issue, I would refrain from starting the car in gear if placed on stands as the wheels would be turning at a reasonable speed even at idle. The consequenses would be huge if it happen to fall off the stands which could be, that you run yourself over or the car slamming into the garage wall damaging the bodywork and paint which you have just invested countless hours on. If going to start it on stands, make sure it is well tied down in case you lean on it too hard while doing adjustments, accidently pushing it off the stands and watching it drive off on its own without driver.
(could be a very funny sight for neighbours thou, watching owner chase after driverless car down road)

[ January 06, 2003: Message edited by: GapLapper ]

 

[Bill Musarra]

Pull the rear wheels or the half shafts and go for it. the half shafts seems better, that way if it falls its got something to land on

Bill

 

[Howard Jones]

I was a little more interested in some idea of cable linkage setup. One good idea came out of this, I put car on the ground and it rolls with clutch depressed. I think clutch is ok. Thanks Robert

[ January 06, 2003: Message edited by: Howard Jones ]

 

[Bill Bayard]

Howard,

Have you tried disconnecting the linkage

and moving the shift rod manually? You

might have a bad or misadjusted cable.

I'm not familiar with the GTD cable setup,

but isn't it two cables? Reversed perhaps,

causing a bind? Just a thought. Maybe you

just need a REALLY BIG hammer!

Hope you get it loose.

Bill

 

[Howard Jones]

Thanks Bill, I did try it with the cables removed from the translator. The shaft that goes into the tailshaft cover goes in and out and back and fourth but it just does not feel like it has enought travel in and out. How much travel should this be? Do any of you guys in england with a GTD have any ideas. I'm gonna go over to Buds and have a look at his. I just gotta HEAR the damn thing run! Note: Don't worry guys if I decide to start it up I will do it with the half shafts diconnected from the gearbox. I was thinking that if everything got to turning inside I might be able to get it to change gears.
Update; just came back from Buds house and his rod's travel is much more than mine. The in and out motion on mine is about .33" whereas his is about 2.5". I think that something behind the rear cover has gone astray? Anybody have simmilar problem in the past?
[ January 06, 2003: Message edited by: Howard Jones ]

[ January 07, 2003: Message edited by: Howard Jones ]

 

[Guest]

Hi Howard

If you run without the drive shafts in, be prepared to get grease everywhere! There is a lot of it in those joints on the sides of the gearbox. Mind you it might have been fun to hear your story of how the grease did go every where. I once had a CV boot split....

I wondered if your box was a 2nd user unit or a recon box? If so then it may not have had the gear selector bits correctly reassembled. It is not necessarily straight forward and a little care is required.

At least the cover removal should be possible with engine and box still in car.

The following advice is not guaranteed but are from mental notes taken when I took my own box apart.

To remove the rear cover you will need to undo the big flat headed screw on the left side (looking from the rear) and take out the spring and ball bearing. Then drive out the roll pin from the shaft sticking out the rear of the box. Remove whatever you have hanging off that shaft, it varies from box to box.

The cover bolts can now be undone but expect oil to come out if you haven't previously emptied the box.

There is a paper gasket between the cover and the main casing so don't go mad forcing the cover off. It can take some wiggling and on mine, it was a bit stiff to remove the first time. This is becaus one of the selector rod shafts (I think that was what it was) seats into the rear cover.

Once off the cover will reveal fifth gear and all the selector rods. Nothing should jump out at you. Inside the cover you will see a cross shaft with the selector drive thing on it. The three selector shafts have U grooves in them and these should align up for neutral.

When re-assembling, align these three grooves up and ensure the cover selector thingy sits into this groove. Point it forward so you can see where it is going as you slide the rear cover back on.

Don't forget to refill with oil!

Hope this helps and if any gearbox expert reads this, firtly, apologies for my technical know how but secondly to help Howard, please advise of any mistakes in process!

Malcolm

 

Hi Howard
I would say your clutch is dragging because of incorrect amount of travel of the thrust bearing. Have you got a clutch with a pressure pad fitted to the fingers that then mates to the thrust bearing?
If you have you can gain an extra bit of clearance by removing it (about 10mm) this will help the stroke of the thrust bearing. Remember that if you have a pressure pad and you remove it then you will need a thrust bearing with a radius at the contact face.
If this fails then check the clutch master cylinder moves sufficient volume to fully actuate the clutch slave cylinder and thrust bearing.
If you mated the Renault box to you engine without checking for thrust bearing clearance and operation, then this is probably the problem.

PS. some of us in the UK have had the trans out so many times that all we have to do is whistle and its on the floor.

Regards
Chris

 

[Howard Jones]

Ok! thanks guys!!! I've got some stuff to check out. I'll complete this story later so that this thread might be of use to somone else.
Thanks again!!!

 

[Guest]

Hey Chris, I agree with your whistle and the box is on the floor. I must have had mine in and out 5 times this year. About one hour each way now when doing it by myself. But wouldn't Howard be able to find neutral even with a stuck clutch or wrong release bearing spacing? When I had the springs pop out of the friction plate I couldn't disengage the clutch, but with the engine off I could get any gear. Howard, you must let us know what the problem was when you find it!
Malcolm

 

[Bill Bayard]

Howard,

I agree with Malcolm. Your gearbox should operate WITH a stuck clutch, bearing, etc. There must be an internal problem. Perhaps someone lost a wrench, when putting the box together?
Pull the rear cover for inspection, and let us know what you find. Don't start the engine and try the clutch! If there is a major problem inside the box, that could prove to be disastrous! Good luck!

Bill

 

[Howard Jones]

Good stuff. I will open up the rear cover and check out the alinement of the shift forks, for lack of a better discription, before I start the motor. Also the clutch fork has no play in it so I think I have two things to solve. More than likely I will need to find a little more travel in the throwout bearing pivot fork assembly. I was thinking about a adjustble rod in this area. Maybe a 1/4" rodend screwed into a threaded coller with the remaining fork rod coming out the other end backed up with a jam nut. If you removed the cross pin from the fork and replaced it with a proper removeable pin I think it would work. Then you could set clearance on the car after assembly. I will try and post pictures of what I find here along with any cool stuff I might come up with. I hope this discussion might help the next guy. Thanks again everyone!

 

[Guest]

IMHO the clutch fork should have no play in it as there is a return spring in the slave cylinder so that the release bearing is on the fingers of the clutch plate all the time ready to operate. Being hydraulic with springs in both slave and master cylinders, the clutch is self adjusting. I am suffering with the bite point not being where I want it on my car right now having changed to the Quaife internals and using a different friction plate. I am solving this by changing the bore size of the master cylinder.

The other thing to check Howard, is that the clutch pipe is 1/4 bore and not the same size as your brake pipes. This occurred on early GTDs and if you have the small diameter clutch pipe you could lose the clutch pedal by pumping it, as the fluid did not return quickly enough back to the master cylinder. This happened to me once on the startline at Brighton Speed Trials when I was going through the motions to pump myself up for a cool start. All it did was freak me out in front of 10,000 spectators. Ooops! Clutch will come back though if this happens. Also I wouldn't suggest you use the Silicone fluid as suggested in the manual either. It eats electrical pressure style brake switches and is hydroscopic.

Malcolm

Malcolm

[ January 09, 2003: Message edited by: Malcolm M ]

 

Hi all
Malcolms comments about the clutch supply pipe size to the slave cylinder are important.
I had referred to the pressure pad because this reduces the effective stroke of the clutch folk by 10mm if you have one fitted (it must be removed), and this can lead to the clutch dragging. If the clutch is dragging then it will not fully disengage and leave the box in a preloaded state which makes it difficult to engage or disengage the gears.
I assume the box was checked for freedom of rotation and engagement before it was installed.
The limited amount of space in the Renault bellhousing means that pre assembly measurements are imperative so that the full stroke of the clutch folk can be achieved.

Regards
Chris
PS, Malcolm if you remove the clutch master cylinder in favour of a larger one make sure that it still pumps the same volume as the original cylinder.
i.e. AP make a 1" cylinder that pumps less volume than the Girling .75" cylinder because it has less stroke.

[ January 09, 2003: Message edited by: Chris Melia ]

 

[andys]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by Malcolm M:
Also I wouldn't suggest you use the Silicone fluid as suggested in the manual either. It eats electrical pressure style brake switches and is hydroscopic.

Malcolm

Malcolm

[ January 09, 2003: Message edited by: Malcolm M ]<HR></BLOCKQUOTE>

To my knowlege, silicone based fluids (most US type DOT 5) are hydrophobic, and will not mix with or absorb water. These fluids are very friendly to most seal materials, have a high boiling point, but have relatively poor compressibility characteristics (for reduced pedal feel, and gets worse as the temperature rises). A nice feature is that accidental spills on painted finishes will cause little or no harm, though it is nearly impossible to thoroughly remove it. I speculate that the "eating of electrical pressure switches" could be due to localized entrapment of water (Since the two don't mix). I don't know its' specific gravity off hand, but if it is for example less than 1.0 and the switch is positioned at a high point in the system (or conversely if more than 1.0 and a low positioned switch), the switch would be in contact with water.

Glycol based fluids (the US type DOT 3 & 4) have a very good dry boiling point, and have very good compressiblity caracteristics which yeilds a good firm pedal feel. The down side of glycol based fluids is that they are hygroscopic and readily absorbe and mix with water. A small amount of that moisture in the system will dramatically lower the boiling point and result in diminished pedal feel, increase pedal travel (requiring pumping), and so on. I suspect that a lot of care is required when filling a new system with a glycol based fluid in humid conditions (not a problem here in Southern California!), and that regular purging with fresh fluid would be a wise practice (as most systems are vented to atomsphere).

In order to determine which fluid you have in an existing system, simply take a few sample drops and dispense them into a small container of water. If it readily mixes, it's glycol; if not, it's silicone.

Maybe someone here has a link to an article on the subject?

Andy

 

[andys]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by AJS:


I speculate that the "eating of electrical pressure switches" could be due to localized entrapment of water (Since the two don't mix). I don't know its' specific gravity off hand, but if it is for example less than 1.0 and the switch is positioned at a high point in the system (or conversely if more than 1.0 and a low positioned switch), the switch would be in contact with water.

Andy<HR></BLOCKQUOTE>

All,

I just re-read my post, and saw I got this specific gravity example backwards.....sigh! The lower S.G. fluid will be displaced and water will go to the lowest point. The higher S.G. fluid will displace the water to the highest point.

Engage brain before.....Though age is a more suitable excuse!

Andy

 

[Paul Thompson 'Hooligan']

Hi all,
Herewith a couple of pictures Howard mailed me reference the problem with his gearbox.

I'll leave Howard to comment.

regards

PaulT

 

[Howard Jones]

Thank you Paul, As you can see the four slots that should all line up ,to be in neutral, were misalined, Bottom picture above. When I lined them up the box seamed to be ok. I have one other question. Bud Jones and I were wondering what the brass round thing sticking out of the rear of the cover is for,top picture. It is attached to the shaft that the shifting fork pivots on with a dowlpin.