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oily

Saracen gearbox.... Other ways of adjusting?

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I have recently replace my fluid flywheel in my Saracen, re-installed the engine etc, and got it all running nicely,.... Although, now, it seems, when it all warms up it mis-selects 3rd and sometimes 5th, yet before the flywheel packed up, all gears were fine.... When I refitted everything I changed the transmission oil for fresh SAE30, as per manuals. The oil that came out was, I think incorrect grade as was very thin, -almost like OM13, and smelled like burnt toast/bread. I checked the adjustment left on the various band adjusters inside the top of the box and compared to a new box I have, there appeared to be a fair bit of adjustment still available, but it doesn't seem to want to 'self-adjust' by using the 'toggling-up' procedure. I'm guessing that the possibly incorrect oil may have caused come 'charring' of the brake bands, and this scorched surface may be stopping the automatic adjustment from taking place.

i have covered about 180 miles since refitting it all, toggling-up before each drive, but, as I said, when warm, it looses 3rd, and sometimes 5th, but always seems to get 1st and 4th, when they are selected..... I have read the manual and it describes another 'top off the box' method using a gauge, (-which I DON'T have), and adjust something as it goes 'over centre', and winding this nut and that nut, backwards/forwards .... Only the last paragraphs in my books are missing.

Can any one with more in-depth knowledge of Saracen gearboxes throw any light on my dilemma, or am I just gonna have to take it all apart AGAIN to fit the new gearbox?,.... I'm seriously hoping it can be adjusted, as I have a wedding to do in it on 10th August!

As I have ALL gears til it warms up, I'd like to think it can be adjusted than be replaced.....

if it is to be the new box, does it have to be set up in a particular gear/or neutral to install it? Or is it just a straight swap-over....

please, PLEASE help, anyone?,... It was really great to get it back running again after so long, but I feel a little let-down that I'm getting problems that weren't there 1st time round.... :o/

 

thanks in advance to all who may be able to help!

 

Matt

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Matt specifically which page are you missing? I may have it (I assume you have the Servicing Schedule I did scan it & send it out to quite a few owners).

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I'll have another look at the manual this evening, thanks Clive!

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Is it correctly selecting the gear or not? Does it select and then slip or does it not select at all? Try changing up and down the box with the top cover off to verify. If its a selection problem then you need to check/adjust the linkages. If its slipping in gear then that's another issue!

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I used to adjust bus pre-select (and semi auto) gearboxes of a similar type and successfully carried out the same procedure on a Fox.You don't need any special (military) tools on that type of box, just a vernier calliper and internal calliper to take measurements. I made a tool to fit in the band adjuster nuts out of a piece of flat steel.

 

Burnt toast smell is not unusual for old oil from that type of box.

 

As a "get-you-home" fix you can tweak the band adjuster nuts up a bit (going too tight can result in the bands dragging), however the back stop bolts need to be correctly set to ensure correct adjustment rates are maintained. I made a set of "T" gauges out of old scrap steel for setting up Routemaster gearbox back stop bolts.

Edited by Grasshopper
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Not overly sure it's actually selecting properly, as when it doesn't work as expected, the GCP just reacts as if neutral has been selected....I'm wondering if the present gearbox had its adjusting toggle mechanism set up correctly when vehicle was overhauled back in 1983, ...-it only had 80 miles on it when I took it on, now it has 1380-odd miles.... Is it possible the bands have only just bedded in, and the adjusters need setting up properly?.... It looks all VERY clean inside, the new oil I put in is still very clean looking too, after 180/200 or so miles I've done since replacing flywheel seal....

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Any volunteers to come and help me see if any adjustment is possible?

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I would offer but I'll be looking after my 5 month old for the next couple of weekends, and much like tracked armour she's great fun to have but high maintenance...

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Thanks, Mr Grasshopper, i know just what you mean!,

Anyone else able to 'throw me a rope'..... ?

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Seems to me that this may well be a selector linkage problem rather than internal to the gearbox.

The internal selectors have to be in exactly the right position to engage a gear. If they are slightly out one way or another then they try and engage two gears together and the gear change pedal stays down. How it achieves this precision is by a plate, carefully machined with exact notches and a spring plunger to hold it in exact positions for each gear to successfully engage the relevant brake band. Now this can wear but it runs in oil and is very lightly loaded so wear is usually none existant. This plate inside is connected to the gear change lever that comes out of the box and is connected by the linkage to the gear stick.

The gate around the gear stick stops it in position for each gear, the linkage moves the gearchange arm coming out of the gearbox and the linkage must place the arm in the exact position. In fact, there is always a bit of wear in the linkage joints so it really needs to place it within a few thousands of an inch then the spring loaded plunger in the gearbox will do the final locating by sinking into its notch. If you disturb the linkage or the gearbox, you have to readjust the linkage which is simple.

Take out the drivers seat and underplates to get to the gearbox. Take out the cotter pin connecting the linkage to the gearchange arm where is comes from the box. You can then turn that arm in an arc, feeling each time the spring loaded pin goes into a notch.If you put the gearstick fully into first with the arm fully at the end of its travel, pin should just slide in. If not, adjust the turnbuckle. Check with the extreme other end (3rd) and again pin should just slip in.

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Thanks John, although Ive not personally disturbed the gearbox itself when i changed the flywheel seal, its possible i guess, that when the gearbox was replced in 1983, that adjustment wasnt made....I'll give that a go, sounds easy enough,... -as I said, I can't believe that the brake bands can be worn out completely to the point they won't self-adjust, ... not after only 1320 miles.....

on that point, how many miles does a saracens gearbox lastgenerally, if its driven correctly and looked after sufficiently oil-wise...?

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Thanks John, although Ive not personally disturbed the gearbox itself when i changed the flywheel seal, its possible i guess, that when the gearbox was replced in 1983, that adjustment wasnt made....I'll give that a go, sounds easy enough,... -as I said, I can't believe that the brake bands can be worn out completely to the point they won't self-adjust, ... not after only 1320 miles.....

on that point, how many miles does a saracens gearbox lastgenerally, if its driven correctly and looked after sufficiently oil-wise...?

 

Oily,

The bands are unable to self adjust if the trigger on the auto adjuster does not meet the square headed bolt on the band. you can check all this out with the lid off the box and see if this is the problem. Then the bands can be reset and the bolts. Once done the procedure is to turn back the adjuster a quarter turn and pedal up again, the adjuster should stop at the previous position, if not, minor adjustments are made. It is all in the EMER section I quoted for the measuring tool.

 

Richard

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Would this still be the case, John, ie, when COLD it seems to work fine, only missing the gear when at running temperature, its almost as if when things have expanded slightly (due to reaching running temperature) the clearances/tolerances required are far enough out to negate correct operation of the mechanism?

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Oily,

The bands are unable to self adjust if the trigger on the auto adjuster does not meet the square headed bolt on the band. you can check all this out with the lid off the box and see if this is the problem. Then the bands can be reset and the bolts. Once done the procedure is to turn back the adjuster a quarter turn and pedal up again, the adjuster should stop at the previous position, if not, minor adjustments are made. It is all in the EMER section I quoted for the measuring tool.

 

Richard

Which section of the EMERS, again, Richard?.... I can't seem to find that post/quote of yours that you mention.... It's probably the one I've been looking at with parts missing.... Saying something about putting a tool in so that it rests on the bus bar groove or something, and taking measurements but its not clear where the measurement are taken from.....

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Oily, you may pick up something from when I wrestled through adjusting the settings on this one's gearbox

 

 

[htmlHappy new Year to all of you and may prosperity bore you!

 

My year started of well with me eventually getting round to spend some time on the gearbox. Having first read up in the manual regarding the slack on the gear pedal, mine definitely was not adjusted correctly. After battling for quite a while adusting this way and that way, it seemed that I had my 1/2" clearance between the pedal and the bulkhead. After bolting everything down and checking the clearance, I was satisfied that it was a job well done.

 

Great was my shock when cycling the gearbox! it was in neutral and all of a sudden the pedal stayed well down. Flabergasted I shifted the gearlever to 1st gear and nearly got my knee against my chin from the kickback! 2nd gear and 4th gear gave the same results as 1st gear returning solidly against the bulkhead with no play whatsoever!. 3rd gear is mild in comparison and left some play to the bulkhead. 5th gear in turn is even milder with even more play between pedal and bulkhead.

 

My opinion is that the gearbox adjustments are way off and needs to be opened. Your opinions, please.

 

Oh, and another thing, what is the "pedal up" procedure, please? I don't seem to pick it up in the manuals that I have. ][/html]

 

http://hmvf.co.uk/forumvb/showthread.php?16817-Saracen-Build-up/page37

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Which section of the EMERS, again, Richard?.... I can't seem to find that post/quote of yours that you mention.... It's probably the one I've been looking at with parts missing.... Saying something about putting a tool in so that it rests on the bus bar groove or something, and taking measurements but its not clear where the measurement are taken from.....

 

 

hi Oily,

I have pasted the post re EMER's on here:

 

 

I am not able to scan you a picture at present, but if you look in EMER V613 Chapter 4, page 3, Figure 1 shows it in use and also Page 5, Figure 4. There is a bar across the top face of box with a rod of 1.4" diameter rounded on the end. There should be a pinch bolt on the bar to hold the rod in position when you take it out to measure the height.

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My illustrations are rather poorly copied and very dark.... Where/what does the rounded lower end of the rod rest on in the gear box?

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My illustrations are rather poorly copied and very dark.... Where/what does the rounded lower end of the rod rest on in the gear box?

 

It rests in the valley of the bus bar

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