Not engaging reverse gear

[SHyslop]

Hello Rob, in for lunch, so far so good. Rear cover plate fixed, old thermostat cover removed and no studs broken so far. Back to yours, the freewheel comes off as a separate unit, nothing will fall out except maybe oil ! There are bolts at the bottom but at the top the unit is held on the gearbox by two long studs, 4 3/4" long, so you'll need to clear them to remove the freewheel from the gearbox. However, there is good news. I have managed to remove and insert the long spring with the freewheel still on the two studs, pulled back just over three inches. Hopefully a picture will be worth a thousand words :

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I've bent the spring down so you can see it is sufficiently flexible to come out of its housing and be removed from underneath, or maybe from the top.
Hoping this is of use and thanks very much for offering assistance: mutual aid will either be the success or failure of older vehicle ownership.

[RobHomewood]

PPS
After further sleuthing I see the type of gearbox mounting strap which I have is illustrated in the Manual Plate D on page F6 as for 38-46 models. So I appear to have a 39 mounting on a 47 gearbox (47 because it has the reverse switch) but my spare gear change mount must be the different 47 model. NB My 39 14 has a 47 16 engine but I bought the original 39 engine, gearbox and many parts with it. I'm glad thats all clear now!

[RobHomewood]

Thanks for your latest thats great news, just in time for me to get out there and get on. I must admit I was procrastinating rather.
Onward and upward!

[RobHomewood]

A frustrating day. Having successfully separated the freewheel housing on the spare gearbox without issue I started on the box in the car. But it turned into one of those jobs that at each stage another factor has to be dealt with. I removed the gearstick remote unit and the restraint strap for the box mounting. i managed to separate the prop shaft from the end of the box - with a lot of rubber mallet work and lever effort - so it dropped down below the shaft OK. I then undid the bolts under the chassis holding the hoop mounting which supports the remote shift unit but it wouldnt come out altogether as the bottom flange is too big to pass the chassis elements and it wont slide off over the freewheel housing. The photo shows the support hoop at an angle, jammed on the freewheel housing which is as far as it will go

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Nevertheless I went on to undo the fixings under the car again for the gearbox mounting lower half cradle. However because the other hoop support could not be removed this part was unable to be removed either. I needed it to go so that I could get to the lower bolts holding the freewheel on. I tried jacking the gearbox higher but it wouldnt move far enough. I am also concerned about being able to replace these bolts afterwards. Currently I am stuck and run out of ideas..

[TonyG]

Hi Rob,

Just looking at your last picture; are the floor panels removable? It looks as though there is a fixing screw on the corner, suggesting this may be the case and possibly allowing you the room to get the gearbox bracket out the way.

I know it seems as though the whole car is in bits but this is what I had to do back in 70s to get the box out of my Tourer. My car has wooden floors of course and, while it is useful to remove the gearbox from within the car rather than lifting the engine and box together, it still involves taking a lot of it apart!

Back in those days, this was the first job we ever did on the old car and was undertaken in the driveway by my brother and me in a slight state of panic. We had put the car on the road, after a 5 year lay-up, while our Dad was on a week’s holiday (it was his car then) and we were worried we had ruined the gearbox learning to drive with no synchromesh. Fortunately it was just the clutch release bearing suffering a lack of lubrication. However, we had the car jacked up, seats out, floor and bulkhead panels removed before we got to all the necessary bolts. Luckily ‘76 was a dry summer and we got it all working and reassembled by the time the old boy got home. Not that he would have been too bothered as it was just a curious old banger of a thing back then!

Good luck and keep us informed of progress.

P.s are you attending the platinum jubilee? It would be nice to see you and the car there.

Tony.

[RobHomewood]

Hi Tont
Thanks for your sage and calming advice. I have booked into the platinum rally and am very conscious of the elapsing time especially as I have other issues on the car to attend to beforehand.
Anyway you are right the floor panels do come out although the chassis framing remains. But it could help to get better access. I have also decided overnight that I will remove the tail shaft assembly and then the oil seal retainer to see if that allows the support hoop to get past. It may still not be entirely removable but if laid horizontal it could give more room to move the mounting cradle away from the bolts in question.
Fingers crossed. But first the sun has come out so I shall take a relaxing constitutional

[RobHomewood]

EUGH! All that struggle was in vain!
Mike Couldry has just told me that what I have is an 'adaption' of the illustrated system for disengaging the freewheel ie the short spring which I have extending from the rear of the freewheel is in lieu of the long spring, not a separate spring. Mine looks like your first photo of your post on 01 April but my spring only just extends into the housing ie about 2" to 3" long whereas yours (and my spare) is 10 1/4" long. I was mislead to believing there were 2 springs partly by the parts book illustration Plate F and H both showing a spring although the latter is not not listed separately. I have not seen any reference to this 'adaptation' anywhere and the Parts book lists the same number for the spring for all models 39-47.
So I now ,rather dispiritedly, have to refit all those hidden bolts etc to put the box back together and try for another solution

[luli]

You can find a description of Free wheel rebuild here:
https://lulis.org/2013/09/07/%d7%a9%d7% ... %99%d7%93/

also here
https://lulis.org/2013/09/12/%d7%a9%d7% ... %95%d7%a3/

Usually the long spring is relevant only in forward driving. It is not relevant in reverse driving since in this situation both forks are engaged together.

[RobHomewood]

Confusing day yesterday. Following my call with Mike Couldry I checked the spare gearbox which is in 2 parts currently and it confirmed that what I was saying about there being 2 springs - the long one inside the reverse shaft and the short one which on the outside of the freewheel shaft and these 2 shafts are end to end so the Bowden cable can run straight through both. Obviously Mike and I had been at cross purposes so I rang him again. Unfortunately I could not persuade him to understand my observations - possibly because my description was inadeqaute or not using the right nomenclature so we had to leave it there.
But I went back to the car and continued with Plan A. After withdrawing the stub shaft from the rear of the freewheel housing and a couple of bolts from the end cover I could see that the support hoop was not going to pass over the casing for removal because of 2 bulges in the housing which were wider than the aperture.
I then removed the footwell floor and found that it did give me better access to the lower fixing bolts/nuts even though it didn't facilitate the moving of the mounting cradle. I removed the nearside floor as well and could get both of the problem nuts off. Having loosened the others I used the rubber mallet to break the gasket seal . This allowed the oil to escape in a relatively controlled manner whilst I attempted to catch as much as possible (unfortunately the drain plug is seized up - more drastic action required later).
So today my job was to part the freewheel casing from the gearbox at least enough to see if the long spring is indeed missing! Well following long negotiations with the rubber mallet I did part the freewheel but it took much more jacking to lift the gearbox and freewheel high enough to clear the mounting cradle and move far enough to the rear to come completely off the long bolts. That was necessary to get into place the new gasket, which I am making later.
I was vindicated to find that the long spring was totally missing from reverse shaft and I could insert the spring from the spare box and found no debris. However at this point ruefully I found that I hadnt actually needed to split the freewheel because the spring could exit from the front of the shaft, where the ferrule had been undone. The ferrule on the spare box was seized so I hadnt beent able to expore this point. So MIke was right in that I didnt need to split the box but he said insert the spring from the rear not the front. I have ordered another spring for the spare box but couldn't find one exactly the same. I will need to reduce the new one's length slightly when it arrives and check whether the diameter and strength etc works OK (the existing one is 8mm dia approx but is a loose fit in the shaft). I plan to reassemble the freewheel and gearbox generally with the long spring in situ but remove it later from the front to compare with the replacement. I can thus restore most of the devastation I have needlessly caused inside the car. I hope to find in due course that I have cured the reversing problem though!

[luli]

I have just made a little experiment on one of my spare gearboxes. I Removed the long spring and engaged the reverse. It works, and reverse is active. I am busy now so I will elaborate later, but read my comment above. I am afraid that you are on the wrong track, nothing to do with the long spring, most probable - some dirt or similar.
This is how the gate should look like when reverse is engaged.

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