Not engaging reverse gear

[RobHomewood]

Thanks for that Luli. I apreciate you taking the time.
I did find that the long spring was missing but as you say that may not have been causing the reverse problem. It must be there for some reason! I can only think that whoever removed the spring or didnt replace it, worked on the assumption that if freewheel was not connected (which it wasnt) it would make no difference. I am trying to reassemble as much as possible before I go away and after I return I can try out the reverse issue as the gate etc has to be reset anyway.

[luli]

Hi Rob,

These are the components which are responsible for revers engaging:

01.jpg (65.9 KiB) Viewed 33312 times

1 is the ferrule 2 is the revers shaft 3 is the free wheel shaft .

This is the revers shaft assembled:

02.jpg (55.81 KiB) Viewed 33312 times

In the next picture you can see the gear moving fork and the gate. This shaft has two positions 1-neutral 2 - engaged. In the neutral position they are separated, not touching.
Engaging is done by the gate pushes the shaft backwards. Now both shafts are united. It simultaneously engages the revers gear and moves the locking gear into the freewheel.
The spring is active when driving forward in the 'fixed' position, but is not relevant in reversing.

[RobHomewood]

Can anyone help please?
I am struggling to mate the freewheel unit back to the gearbox ('47 14/16 box) which is in situ in the car. This is in fact the third* time I have taken it apart and reassembled it but each time the problem is the same but the previous random solutions dont seem to work.
The biggest problem is that being in situ I cannot move the freewheel apart enough to look inside because the gearchange support hoop is blocked from removal by the chassis members. This hoop also stops the gearbxo support from being removed and the max moevement I can get is between 1 and 2 inches- just enough to get to the lower fixings of the freewheel section.
The freewheel section is still threaded onto the 2 long studs and will move up to about 1" from closure and is then blocked. This appears to be because the main shaft is not accepting the splines of the tail shaft H6 into the main shaft G25. I have tried multiple positions for H6 by by levering H43 out of H5 (already on the splines OK) which allows me to turn the tailshaft H31 which engages OK with H6. The trouble is I haven't got enough of a gap to see into the front of the freewheel housing to check what is fouling. I have tried removing the tail shaft H31 and looking into the shafts from that end with a mirror and light but still cant seem to get the positioning right. What am I missing?
My first question is: are all four splines the same size ie the shaft will fit in 4 positions or are they different size ie only one orientation will work?
My second question: any suggestions for getting this to work in this confined location?
*the first time was to replace a missing spring in the reverse shaft, the second to fiddle the freewheel cable into the narrow shaft in the freewheel shaft which extends the reverse shaft and is slightly distorted and the third time was to take the tension off the long spring so that I could refit the ferrule at the front end of the reverse shaft.Had I known when I started.................

[luli]

The back side of the main shaft. The freewheel ex-center and free/fix gear are mounted on it.

shaft.jpg (31.25 KiB) Viewed 33204 times

This is its profile

prof.jpg (28.13 KiB) Viewed 33204 times

here are both parts mounted on the shaft

both.jpg (42.44 KiB) Viewed 33204 times

for that they must be aligned.

aligend.jpg (67.18 KiB) Viewed 33204 times

not Aligned.

not.jpg (38.47 KiB) Viewed 33204 times

To align rotate the freewheel shaft until they are aligned. Than it will slide in nicely .

[RobHomewood]

Hi Luli
Thanks for being so patient with my queries and thanks for the beautifully clear photos. They do reassure me that I was on the right track by trying to align the splines but the problem remains that I cannot see the splines with the box in situ to do this. From the gap between the freewheel casing and the gearbox casing the freewheel locking dog obscures the view of the mainshaft and its splines and from the rear my only view is up the tailshaft sleeve (tailshaft removed) with a mirror and light. However studying your pictires and the parts list illustrations (unfortunately split across 2 figures) I shall try removing the locking dog temporarily from the set up and hopefully being able to line up the other components with the better view. I would then have to gently ease off the freewheel unit keeping the shafts aligned, to reinstall the locking dog. This latter operation requires tilting the locking dog to insert under the operating shaft meaning the locking dog needs to be completely off the main shaft. My worry is that I will not be able to get the freewheel housing sufficiently clear of the main shaft in such restricted circumstances.
Here's hoping it works
Rob

[RobHomewood]

Just a quick update.
My idea as above did not work becasue the freewheel unit would not move far enough to get the locking dog off the main shaft.
But I did eventually work out a method of unlocking the splines by pressing freewheel operating shaft H40 -which protrudes out of the box with a spring- fully in with one hand whilst pushing and turning the tail shaft H31 with the other to 'feel' where the splines coincided. Thus I managed to get the freewheel to marry with the gearbox- well almost. There was some resistance with the last couple of mm but I got there with the mallet.
I havent been able to test it yet as I have to re assemble lots of bits i removed for access etc etc but I have progress!
Thanks for your help
Rob

[luli]

Yes, this is the right method. Removing the two long studs helps to do it easier.

[RobHomewood]

I got the freewheel re-assembled as noted above and put everything back but I had problems with the result. All gears were jammed solid at first. I played with the selector dog position (the notch in the shaft allows a fair degree of adjustment) and with the detent springs and managed to get the forward gears working or the reverse but not at the same time. Persistance eventually got them all freed off but reverse would only go in if held against the long reverse spring pressure ( quite considerable pressure). I changed back the reverse detent spring to the proper stronger one, rather than the 'forward' type one I tried, and this improved things slightly in that the stick would go into reverse and stay and operate but as soon as the clutch is pushed out or the momentum is eased the stick jumps out of reverse.
The reverse shaft long spring is the original from the spare gearbox. As I understand it the detent ball and spring is supposed to click into the notch in the reverse shaft to hold the stick in gear. I wondered whether to try cutting down the reverse shaft spring to reduce the pressure but not sure if that is indeed the problem?
Any suggestions? (I have checked that the reverse is not limited by the gate ie it could travel further if the gearbox would let it)
Rob

[luli]

I suspect that the issue is in springs 50, 49 or the corresponding balls (47, 46)

gearbox-case-1.jpg (74.15 KiB) Viewed 32969 times

[RobHomewood]

Thanks Luli
I am presently occupied trying to find studs to get the exhaust manifold back on in order to get to the National Rally so I have decided to leave the gearbox as it is for now and maybe discuss it with others at the rally. Assuming I make it of course!