Prompted by the parking brake thread I started thinking about the unique features on Fodens. In spite of working for a Foden repair agent for a couple of years I don’t ever recall any diff problems , and we regularly maintained quite a few eight wheelers. We certainly changed a fair number of hub oil seals and I still have my sawn-off allen key for the grubscrew in the locknut safely stored in my Gardner toolbox. However we did not see many tractor units except our own S80 which was used for taking trailers for test. IIRC the diff on this had a large circular housing on the bottom of the bowl, since I never did more than jack up the back end; being very careful on all Fodens not to jack under the bowl; I really don’t know why it was shaped like this, Any ideas?
Since we had comparatively so much trouble with the Foden gearbox I’d better leave sleeping dogs lie!
that brings back an amusing memory . back in the mid 60s i drove a dilapidated fg 6 wheeler , maintenance was minimal , any major problems take it to sandbach otherwise let it develope . started her up this particular morning went about 10 yards and stopped . i left it running in gear at got out to have a look . all ok propshaft rotating , no noise from a broken halfshaft ? gaffer sent for foden’s mechanic and he came and took the halfshafts out and eventually decided to lift the diff out . the crown wheel was completely worn away until the pinion wasn’t even making contact . the fitter reckoned you could have shaved with the edges of the crown wheel . the main problem with foden diffs was the tendency to wind up if you overdid silent overdrive down the hills . cheers , dave
Hiya…same here Rigsby… you know what Graham was like with fodens more the merrier.
the bronze diff use to ware away and as Dave said you could shave with a tooth they got that worn.
i was in Malta a few years ago there was two Foden diffs lying on the ground…Wow how do i get that
hundredweight bronze home…
i smashed a diff to bits on building site when i was at Richardsons one time. it was about 5 years old
and done a lot of work.
now tyres and double drive diffs…fffuuuffff you need to have all the
tyrers the same circumference, its no use sticking a two new tyres on one axle and 3 parts worn on another
you have to marry them up or you have a pile of bronze in the diff oil…by the way its a lovely colour and texture
and stinks like cat pee. Foden diffs on double drives…forget them
John
Time to join in I guess!! I think that only the tractor units had that extra circular ‘sump’ on the diff bowl, none of our rigids had them. We always jacked them up under the diff bowl with no issues, not when loaded though! We had bearings worn out on the worm, mainly due to the crap synthetic oil that BP ‘forced’ onto our TM, and the wheels themselves wore away as has been said for much the same reason though we never actually replaced one. Our Foreman rang Fodens one day to ask what backlash was acceptable, their reply went something like “When the worm turns several times and the wheel doesn’t then it is time for a new wheel” so Rigsby’s had reached that stage!! We always kept a spare diff built up and then rebuilt the knackered one in slack periods. Out S50/39/S80tippers had 5.75 .1 ratios, the tankers 5.25.1, but the Haulmasters had the 5.25 ones across the range. Tilcon, being tight, didn’t specify the optional third diff so tyre mating was essential as has already been said. Hub seal failure was very common, there were various different ideas tried including double seals and doing away with the halfshaft seals and making the hubs oil lubricated instead of grease but none really worked. Finally Stemco leather seals cured that problem but you had to hammer the hub nuts up really tighter than recommended by Fodens, also building the axles up with Belzona putty where the bearing had spun on them helped.
As CAv551 says, best not mention the gearbox… 
Pete.
Don’t know about diffs, but I’ve had more than a few half shafts go on me on the old S 21s. Could be down to ’ driver error ’ I suppose , but it seems odd that I’ve never done a half shaft on any other motor. Eddie.
probably wear in the diff eddie , a quarter turn on the pinion before it engages properly produces a lot of force and eventually either the diff or a halfshaft will have to give , cheers , dave
Don’t remember too much about the fodens, except my dad swearing about his on a regular basis, but some bits which stick in my memory are the side windows, with that little lever to hold them closed, otherwise they used to slide open on their own; the buzzer which used to sound for alternator and oil pressure, which often used to stay on after the lights had gone out, and the fuel gauge outside on the tank rather on the dash. Oh, and the less than adequate heater. Having said all that, I still used to love going with dad any chance I got, even though I used to have to sit in the security hut at navyard wharf when dad was loading, which could take anything from 1/2 hour to 4 hours. Good old Slaters Transport 
Quite possibly rigsby, I’m no mechanic, I only know that the motors that we used had done more miles than the space shuttle before we even climbed into the cab. Eddie.
I must remember that one! 
We never had a halfshaft break, however propshafts sheared off at the drop of a hat (especially with trucks fitted with the air clutch) until Fodens fitted the heavy Kempf type shafts. The amount of shafts we changed on that steep pinch by The Mermaid on the Staffordshire Moorlands when work was slack and the trucks wwere running clinker from Blue Circle at Waterhouses to their Hope plant. 
Then diff bearings started overheating, we were unaware that the shafts were hollow right through and, with the monthly greasing of the sliding joint, the grease eventually stopped the shaft sliding easily when the axle deflected! I seem to remember that Foden recomended greasing them every 48,000 miles then, no more problems.
Pete.
i think the trouble was probably that foden hadn’t uprated anything since the gardner 180 . when bigger horsepower arrived propshafts , diffs and eventually even the foden 12 speed were outdated . cheers , dave
rigsby:
i think the trouble was probably that foden hadn’t uprated anything since the gardner 180 . when bigger horsepower arrived propshafts , diffs and eventually even the foden 12 speed were outdated . cheers , dave
Ours all had the 180 Dave, apart from a pair of S80’s with 220 Rollers, but they had stronger shaft’s anyway. Most of the propshaft’s broke when snatching for low range on banks, The Mermaid and that steep pinch out of Hognaston village before the by-pass were favourite places! Of course we had a few that lost the short prop between the diffs on Motorways, goodness knows where the shaft’s went as we never found them! 
As you say the worm diffs and 12/8/9 or whatever you wanted to call it gearbox also struggled with higher BHP and the ones in the Rolls engined ones literally shook themselves apart!
Pete.
windrush:
Time to join in I guess!! I think that only the tractor units had that extra circular ‘sump’ on the diff bowl, none of our rigids had them. We always jacked them up under the diff bowl with no issues, not when loaded though! We had bearings worn out on the worm, mainly due to the crap synthetic oil that BP ‘forced’ onto our TM, and the wheels themselves wore away as has been said for much the same reason though we never actually replaced one. Our Foreman rang Fodens one day to ask what backlash was acceptable, their reply went something like “When the worm turns several times and the wheel doesn’t then it is time for a new wheel” so Rigsby’s had reached that stage!! We always kept a spare diff built up and then rebuilt the knackered one in slack periods. Out S50/39/S80tippers had 5.75 .1 ratios, the tankers 5.25.1, but the Haulmasters had the 5.25 ones across the range. Tilcon, being tight, didn’t specify the optional third diff so tyre mating was essential as has already been said. Hub seal failure was very common, there were various different ideas tried including double seals and doing away with the halfshaft seals and making the hubs oil lubricated instead of grease but none really worked. Finally Stemco leather seals cured that problem but you had to hammer the hub nuts up really tighter than recommended by Fodens, also building the axles up with Belzona putty where the bearing had spun on them helped.
As CAv551 says, best not mention the gearbox…
Pete.
The pan on the bottom of the diff casing was only on tractor units or perhaps on single drive 6/8 wheelers this was to hold extra oil I was told by Fodens when I enquired why they were like that, I do remember having a laugh when a local breaker in the North East charged more for a second hand diff from a tractor unit he claimed that the crown wheel was bigger & worth more for scrap when I told him that the it was for extra oil he thought I was having him on, Regards Larry.
windrush:
rigsby:
i think the trouble was probably that foden hadn’t uprated anything since the gardner 180 . when bigger horsepower arrived propshafts , diffs and eventually even the foden 12 speed were outdated . cheers , dave
Ours all had the 180 Dave, apart from a pair of S80’s with 220 Rollers, but they had stronger shaft’s anyway. Most of the propshaft’s broke when snatching for low range on banks, The Mermaid and that steep pinch out of Hognaston village before the by-pass were favourite places! Of course we had a few that lost the short prop between the diffs on Motorways, goodness knows where the shaft’s went as we never found them! As you say the worm diffs and 12/8/9 or whatever you wanted to call it gearbox also struggled with higher BHP and the ones in the Rolls engined ones literally shook themselves apart!
Pete.
Never had any lumber like you describe Pete with the Eaton/Kirkstall/Scania/Volvo/Guy/Group and Rockwell diffs,in fact I can’t recall ever having trouble of any kind with these diffs,but had the odd shaft break on the little 82’s and of course quite a bit of lumber with the Group hub reductions but no diff failures on the Seddon diff,sounds like running Fodens was a real bundle of laughs Cheers Dennis.
Bewick:
Never had any lumber like you describe Pete with the Eaton/Kirkstall/Scania/Volvo/Guy/Group and Rockwell diffs,in fact I can’t recall ever having trouble of any kind with these diffs,but had the odd shaft break on the little 82’s and of course quite a bit of lumber with the Group hub reductions but no diff failures on the Seddon diff,sounds like running Fodens was a real bundle of laughs Cheers Dennis.
Well Dennis, when you have a fleet of 40+ eight wheeler tippers on heavy work, getting bogged down on sites etc, breakages are par for the course. These lads who only go ‘off road’ when they turn into a lay-by have no such problems! To be fair Fodens own diff gave few problems apart from occasional bearing collapse and was very strong but not free running like a Hypoid axle so less economical. By far the worse diffs were the Eaton ones in the Sed Ak 400’s and I think that every one of ours shed teeth off of the rearmost crownwheel, yet the later Fodens with the same Eaton back end after they changed from Rockwell ones (they were too heavy) gave no trouble at all. I remember visiting the Commercial Show at the NEC and on the Eaton stand was a sectioned diff assembly, I said to the salesman that it was unusual seeing one with all its teeth intact and he just nodded and admitted that they had a few issues with them but hopefully they had sorted it! To be fair, once the Sed Ak diffs were replaced (some under warranty) they were no further trouble.
Pete.
hiya…as you say Pete off road…i went to the first job on the 8 leggers in Altringham… Atlantic st, they was putting
a new main in, i stopped and said where do want it mate, over by the machine, i could see it over two fields, i said that far
he just said take it back if you want…i set of in this man 8 legger the sh.te was over the top of the bumper but she
kept going straight to the machine (about a 3rd of a mile) i never put the cross locks in she just did it. got there a chap
(in waders i think)opened the door and up it went, dropped her down he had signed up and away. i never thought a landrover
would have got through it…i run there for 2 weeks…with other trucks.those MAN 8 leggers will go anywhere…same backend
as the Merc double drive…
John
Larry you are quite correct, the single drive rigids did have that extra capacity diff bowl but then they usually had the reduction hubs as well which I assume would take more oil that the standard ones, maybe that was the reason? The Albion eight legger from the fifties (Caledonian?) had a similar shaped diff bowl I believe?
Pete.
windrush:
Larry you are quite correct, the single drive rigids did have that extra capacity diff bowl but then they usually had the reduction hubs as well which I assume would take more oil that the standard ones, maybe that was the reason? The Albion eight legger from the fifties (Caledonian?) had a similar shaped diff bowl I believe?
Pete.
That’s correct Windrush, Regards Larry.
Wow didn’t the splines on those short propshafts between the two diffs wear ! It must have been because of the ‘missing’ 3rd diff. And talking of 3rd diffs my old mate Vic Goodsell, alas now tinkering with the pearly gates, had one of HE Woodcock’s AEC Marshalls loose its complete 3rd diff one day. Going back to the inter-shafts, almost no amount of dire warnings could convince some of the ODs that their lorry needed a new shaft - until one of them actually lost one. I don’t know if I am imagining it, but I think the output flange on the front diff was like the gearbox one and part of the shaft, thus making it a bit of a pig getting the prop bolts undone because it ran so much closer to the casing.
To get rid (very temporarily!) of slack in the splines of the sliding joint on propshafts we used to pack them with Junior Hacksaw blades and grease them well, it got them through the test OK! 
The Kempf shafts, being the same diameter from end to end, didn’t have that problem.
Off topic slightly, I was trundling up the A610 dual carriageway one morning heading for Nottingham and spotted a complete short shaft from between the diffs laying in the outside lane. In my mirror a MGB was approaching rapidly, I tried to warn the female driver but to no avail and BANG, the car was airborne! It landed on the central reservation with the sump ripped open and one very shaken lady.
Pete.