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Scammell Pioneer Restoration


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  • 3 months later...

At last progress has been made.

Spent today bolting a load of bits onto the chassis, have done the trailer brake servo, trailer air taps, one of the air tanks, most of the pipework, the neate brake reaction lever assembly, and the neate brake lever assembly. Had a few probs with the second air tank so it had to come home again for some remedial work.

There will be photos in due course, I didn't have my camera with me today.

 

Richard

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  • 8 months later...
  • 1 month later...

Got one of the side cases off the back axle at the weekend, it having resisted most of the way. Unfortunatly it left the inner bush behind so got to make up a tool to try to remove that now. Fathers going to keep it soaked in diesel all week to help it along.

 

Richard

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  • 1 month later...

Had a good weekend on the Scammell, got front hitch bracket and weights bracket on, not easy considering the gap for the hitch bracket was about 3mm narrower than it was itself. Also got the first side gearcase back on the back axle and i was pleased to find it can now be rocked up and down with one hand, a task which required the telehandler to push up and down on it before!

 

Richard

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  • 3 months later...

Been working on the rad. Below is the matrix, tried cleaning all the paint and muck off with a caustic soda solution, but while it cleaned all the muck and dirt up it didn't remove the paint as i had hoped. I'm in the process here of stripping the yellow! hammerite the previous owner had applied to the whole vehicle. Afterwards we steam cleaned the whole thing to remove all the gunk.

 

P1000935.jpg

 

Below are the header and bottom tanks after blasting and priming, i've had some new rubber gaskets made and am just waiting on some nuts and bolts before putting the whole thing back together and plonking it on the chassis.

 

P1000936.jpg

 

Richard

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  • 1 month later...

Been working on the gearbox and stumbled on a problem i'm wondering if anyone has any suggestions on.

We were hoping to not have to strip the whole thing and having had the side cover off, everything looks pretty good inside. Planned on removing most of the external bits and pieces for cleaning to clean out oil pipes, sort the "gummed-up" PTO unit and un-sieze the handbrake etc.

Got everything off the back of the box which reveals the view below.

 

P1000943.jpg

 

What you're looking at is the pipe which runs inside the top countershaft and lubricates all the needle roller bearings via cross-drillings in the pipe and the top countershaft itself. According to the manual there should be two cross-drillings and then the oil carries on down the top countershaft and through a final cross-drilling into the last set of needle rollers. I wanted to get the pipe out to replace the dowel pin which is there to stop the pipe from turning, and which can be seen bent in the photo above. Heres where the peculiarities start.

I managed to pull the pipe out and.....

1) theres only one cross drilling when the manual clearly shows 2.

2) the end of the pipe has an internal thread, which i can't see in the cross section in the manual.

3) most strangly, there was a length of studding the same thread as that in the end of the pipe about 1/2" long just slopping around inside the top countershaft. I can't understand why this would be there, looking at the cross section in the manual, if this had been installed in the end of the pipe the last set of needle rollers wouldn't recieve its lubrication.

 

Below are photos of the pipe with the length of studding, and an end view of the pipe showing the bent dowel pin.

 

P1000944.jpg

 

P1000946.jpg

 

Below i've included a scan of the manual showing a cross-section of the box. The pipe in question can be seen running most of the length of the top countershaft, in the top right corner of the view.

 

gearboxsection.jpg

 

We have a few theories and ideas, but any suggestions on whats going on and what route to take from here are much appreciated.

 

Cheers, Richard

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Common problem, the tube has seized in the shaft due to getting hot and expanding, (it is a close fit, notice the blueing) this is probably because the plug has fallen out, letting the oil pass through without any pressure in the tube to force it out through the side holes, I'm sure there should be two holes

Edited by gritineye
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Thanks for that Bernard.

 

I've read your box rebuild, everything certainly points towards having to split the box.

But i still wonder why there isn't two holes and also if the end is plugged how is the last dog clutch on the top countershft lubricated? the cross-section suggests that oil is meant to come out the end of the pipe, down to the end of the top countershaft and out through the cross-drilling inline with said dog clutch. Neither the pipe or the plug have any signs of "staking" to hold it in position. There is some sign of heat discolouration, and i notice that mine has a similar wear pattern to where yours is worn between the two cross drillings. I presume the pipe should be parallel, since it just sits in a drilled and probably reamed hole. I'll take another look in the morning, see if there is another cross-hole which has been blocked with debris.

 

Watch this space. Cheers, Richard

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Common problem, the tube has seized in the shaft due to getting hot and expanding, (it is a close fit, notice the blueing) this is probably because the plug has fallen out, letting the oil pass through without any pressure in the tube to force it out through the side holes, I'm sure there should be two holes

 

Sounds about right, the plug in the end ensures the oil is forced out the hole into the tiny gap between shaft and tube then along the lenth to the end bearing.

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The tube seems to be a metering device, if it was not there the flow rate would have to be much higher, the gear needles get a constant small amount with an extra pusle each time the holes coincide, so the oil pressure is maintained throughout the hollow shaft and tube (and the entire system), and a constant flow is maintained to the end spigot bearing which takes a lot more load as it supports the shaft.

 

The dog clutches, gears, and other bearings are lubricated by splash, squirt, and oil dragged up from the sump and the 'sumpletts' towards the rear of the casing below the gears.

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Yeah, the oil oozing out the gap between the pipe and shaft was something that hadn't occured to me - d'oh.

 

With that in mind i had a thought about improving the oil flow between the pipe and shaft thus aiding lubrication and cooling, see what you think of this - I thought about machining a tiny flat down the length of the pipe from the front end cross-drilling to somewhere coincident with the rearmost bearing and in line with the cross-drillings, probably only about 0.25mm off the full diameter. This would introduce oil between the pipe and shaft, without resulting in a drop in pressure because the limiting factor on that is the gap between pipe and shaft and the length between the front most cross-drilling and the end of the pipe.

 

Comments any. Cheers, Richard

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Not to sure if extra oil would push the pipe off center and wear the back side of the tube?

 

Thats a very good point.

 

Not too sure about that, I think you would just weaken the pulse to both bearings, but I can measure a shaft if you need the hole spacing to drill a hole.

 

Right, thats that idea aborted then. I'm gonna have a good poke around see if i can find the hole at the weekend, it must be there somewhere and i didn't really look too hard when i took it out. I'll come back to you if i'm unlucky.

 

In the meantime, anyone know where i can get handbrake linings? I've emailed Chelsea Frictions, but haven't heard anything back yet.

 

Cheers

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Quick question. I'm in the process of spliting the box, and the manual says theres two bolts inside the box. Are they accessed through the side cover on the off-side? I thought i'd ask before going to the effort of turning the thing over and then finding they're not there.

 

Cheers, Richard

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  • 3 weeks later...

Alas, the best laid plans of mice and men!

 

Got the offending bearing off today, but gear AQ in the diagram above from the manual doesn't want to come off. It should have a parallel bore and slide off the needle rollers easily, instead it jangles about seemingly jammed on. This is the gear that would have been fed with oil by the absent hole in the top oil baffle pipe, which leads me to think that a groove has been worn in the bore of the gear, and the needles are locking the gear on by getting themselves part way between the new groove in the gear and the groove in the shaft they are supposed to be in. Does that make any sense?

 

And so we are now on the look out for some replacement bits, namely the top countershaft and gear AQ with its rollers and possibly gear AP with its rollers. The bearing surfaces and rollers that form the interface between the top countershaft and primary shaft are very good, so i would hope that some careful use of the micrometer would see us being able to re-use the primary and the needles.

 

Can anyone help with bits? Bernard?

 

Many thanks in advance, Richard

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  • 1 month later...

Took delivery today of second gearbox courtesy of Steve from Rotherham. Have removed the side cover and so far it looks good. Have removed the oil pipe that was offending on the other box, and it has all the correct drillings, but again the plug from the end was not in place and was just loose at the bottom of the hole.

Will get it split open next weekend for a closer inspection so, fingers crossed.

 

Richard

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  • 5 weeks later...

we're back on track now, the second box is mostly good, with just the needle rollers between the input and top countershafts being U/S, i can't figure for the life of me how they end up in such a state. But all is ok, i will replace the offending bits with parts from box no. 1. Have now stripped box as far as i'm going to, see below

 

P1000979.jpg

 

and are now on with rebuidling the four shafts ready to put back in. Picture below is the mainshaft in early stages of reassembly.

 

P1000984.jpg

 

I've just taken delivery of new oil seal for output shaft, and i have to get or make dowel pin for the infamous oil pipe. I'm going to re-insert the plug in the end of the oil pipe and stake it in place. So, fingers crossed, everything is back on track.

 

Richard

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