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PollyMobiles Rebuild

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pollyp

pollyp

Club Member
Chances are Paul the centre of the grinding wheel is your issue. Stabbing in the dark having not seen it

yeah the center of the wheel ain't exactly precise or smooth. I remounted it several times till it no longer sways sideways, tried the redresser to reduce most of the undulations and it's close enough, not perfect but'll do the job.
short of going out n buy a new wheel.
 
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pollyp

pollyp

Club Member
got more toys tday,
the quick change arrived

IMAG4368.jpg


regreased these o-ring plungers

IMAG4369.jpg


installed base

IMAG4370.jpg


and adjusting the tool is so much easier and the way it cuts seems abit more rigid :cool:

IMAG4371.jpg


definately not happy with these red carbide tipped cheapo tools cos they blunt easily and when I try grinding em, the soft steel body grinds easily but the harder carbide tip is so much more difficult to sharpen, takes alot of time & effort each time (especially with an unbalanced grinder shaking everything)

the luvely new sharp indexable carbide tools arrived :cool::cool:

IMAG4366.jpg
IMAG4367.jpg


debated whether to return or try it out.
maybe the heat or frustration got to me but after the cheapo tools kept blunting and grinding is pita, thought fookit I already paid and got em here lets see if they're any good

IMAG4373.jpg


fit in holder

IMAG4375.jpg


centered and tested on softer Alu rod and omg it cuts it like soft butter.
the swarf is soo consistant and finish is silky smooth :cool:
ok I'm sticking with these carbide tips.

IMAG4377.jpg
 
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pollyp

pollyp

Club Member
to fix the loose LSD driveshaft I ordered this 60x68x60mm sintered bronzed plain bearing and lathe the outer dia till it fits inside the loose LSD bore

$_57.JPG
 
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pollyp

pollyp

Club Member
to fix the loose LSD driveshaft I ordered this 60x68x60mm sintered bronzed plain bearing and lathe the outer dia till it fits inside the loose LSD bore

View attachment 50086
ah crap I read the wrong measurements, no wonder 60mm seemed abit too large for a driveshaft o_O
I'll have to return it, then remeasure the actual shaft before ordering again :rolleyes:
 
ah crap I read the wrong measurements, no wonder 60mm seemed abit too large for a driveshaft o_O
I'll have to return it, then remeasure the actual shaft before ordering again :rolleyes:
Use thicker walls to lathe down, that way both inner and outer diameter will be square to each other, which is no guarantee abd damn near impossible on an un-machined surface
You probably know this but just in case :)
 
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pollyp

pollyp

Club Member
side of the engine having another big oil leak

IMAG4379.jpg


crossmember crack getting bigger after several launches at santapod, really needs replacing soon

IMAG4380.jpg


normal debris on the gearbox plug from the LSD plates

IMAG4381.jpg


LSD oil still good

IMAG4382.jpg


the driveshaft is 25.92mm dia

IMAG4383.jpg
IMAG4386.jpg


the loose bore of the LSD casing is 26.2mm dia, 25.8mm long with a 2.50mm chamfer

IMAG4385.jpg


just ordered a 25.4 x 28.58 x 38.1mm plain bearing

bush.jpg


but according to calcs I'd have to machine the bronze sleeve down to just 0.14mm about the same as a drinks can!!! :eek::eek:

sleeve.jpg
fit.jpg


even with my limited lathing skills, that's near impossible on a semi-accurate mini-lathe without the wafer thin walls collapsing.

my options are either to take out the gearbox, strip the LSD and enlarge the hole for the bronze bush (too big for my lathe, would have to take to another machinist),
or I lathe the inner driveshaft abit (reducing the oiling grooves and possibly weaken the shaft)
 
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pollyp

pollyp

Club Member
unless a 26mm dia tin can exists out there, I feel my best option is the big task of taking out the LSD and get someone to bore the hole & fit a thicker sleeve

sleeve2.jpg
fit2.jpg
 
OP
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pollyp

pollyp

Club Member
ok think once this bronze bush arrives tomorrow, I'll first try to lathe this super thin sleeve.
if it doesn't work then I'll have to remove the LSD and get it machined.
 
ok think once this bronze bush arrives tomorrow, I'll first try to lathe this super thin sleeve.
if it doesn't work then I'll have to remove the LSD and get it machined.
Is the drive shaft inner C.V too small or the LSD hole too large?
If the CV is too small I'd get a new or different one if the LSD is too large isn't it the problem of whoever made it? Or has it been worn somehow?
 
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pollyp

pollyp

Club Member
Is the drive shaft inner C.V too small or the LSD hole too large?
If the CV is too small I'd get a new or different one if the LSD is too large isn't it the problem of whoever made it? Or has it been worn somehow?

the RH LSD hole is slightly too large. the LH hole is perfactly fine.
not sure if it was made too large or if it was worn larger over the years cos I barely remember it didn't make the high speed wobbly noise when new.
 
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pollyp

pollyp

Club Member
is,nt there some space to insert a bronze bush here paul, about 3mm wide and behind the seal

View attachment 50112

ur a clever guy frank :p

measured some more details and just look at how close this dust shield is to the gearbox casing around the oil seal (circled).
coupled with the shaft wobbling about by 0.28mm I suspect this could be where it'll be rubbing/whirring at high speed and during turns.

fitting 1.jpg


and ur spot on, there's about 3mm gap between the oil seal and the driveshaft face.
I could lathe the oil seal surface 3mm further along, and perfectly match the 26.2mm dia bore where it touches by approx 2-3mm to stop it wobbling.
this shifts the shaft 3mm inward so will need to cut a new square groove for the spring clip to keep it retained snug,
and remove the dust shield to clear the gearbox (circled).

lathed driveshaft.jpg
lathed driveshaft 2.jpg


hmm actually, before the big task of lathing the shaft I wonder what if I first simply knock that metal dust shield off and see if it's stopped the rubbing noise?
then if it still rattles/whirrs/knocks, I'll try lathing it to fit more snug.
 

SuperUno

Buy & Sell Member
I run the long shaft without a retaining clip, have done for years. I just can not fit the shaft to the LS Diff with the clip in place, only issue till now was the shaft falling out when i left it hanging when doing a different job on the front suspension. Caused a massive puddle of g/box oil on the drive, which I think I just about got away with hiding from the missis! :oops:
 
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pollyp

pollyp

Club Member
I run the long shaft without a retaining clip, have done for years. I just can not fit the shaft to the LS Diff with the clip in place, only issue till now was the shaft falling out when i left it hanging when doing a different job on the front suspension. Caused a massive puddle of g/box oil on the drive, which I think I just about got away with hiding from the missis! :oops:
woopsidaisy, plenty of towels n powder on that puddle :p

was the clip just not allowing the shaft to be inserted? (the clip has to be bent to a certain dia and kept perfectly centered & concentric to the shaft with grease, or else it'll simply shift offset & jam),
or was it not retaining the shaft once fully inserted?
 

SuperUno

Buy & Sell Member
A lot of thinners and washing up liquid got the mess cleared up in the end...

I tried everything, to get it fitted but nothing worked...
 
OP
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pollyp

pollyp

Club Member
BTW the way you can create the drawing so well, you must be able to get a job doing that sort of work!

thx m8, hope I can soon overcome my anxiety to find a job I'll enjoy.
that was just some precision measurements and very simple 3D modelling in solidworks ;)
 
Paul
What about trying a later CV cap? They're larger than yours and might be a better fit
There's always my K11 to measure if you wish
 
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pollyp

pollyp

Club Member
received the bronze bush tday

IMAG4389.jpg


the sintered bearing is very porous and oily

IMAG4390.jpg


began lathing it to 26mm bore/26.2mm dia
this porous oily sintered bush creates very fine dusty oily mess that clumps together and to everything so will be a pain to clean

IMAG4391.jpg


I managed to bore the insides to exactly 26mm but when cutting the outer dia I only managed to get down to 26.5mm (0.5mm thickness) till I noticed it beginning to flex at the end and cut unevenly

IMAG4392.jpg


it slots so nicely over the driveshaft, gotta love precision :cool:
BUT it wasn't thin enough cos it doesn't fit inside the LSD hole, it had to be 26.2mm :rolleyes:
so that was an interesting challenge but wasn't feasible.

IMAG4394.jpg


so lets fit the driveshaft back in with the 0.3mm slack but without the dust shield

IMAG4397.jpg



went for a drive and the subtle whirring above 40mph is still there
 
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pollyp

pollyp

Club Member
the LSD reload is wearing quite progressively now

lsd.jpg


predicted to last approx 10-15k (bout 1-2yrs) till it gets too loose

forcast.jpg
 
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pollyp

pollyp

Club Member
tday received a pair of HSS square ends to sharpen

IMAG4408.jpg


and a small pilot hole bit

IMAG4409.jpg


I was looking through some bike bits in the garage and found that the seat posts are 27mm dia alloy and this old fork had a 25x28mm dia steel shaft, perfect for machining a super-thin sleeve

IMAG4399.jpg


I recently saw a vid about how a mini-lathe could cut better by running in reverse


so curiously I tried it on mine and it works quite good.
following andyH701 advise, I managed to lathe the alloy seat tube down to precisely 60mm for using as an inner supporting bung, tis an awesome feeling to see such accuracy :cool:

IMAG4400.jpg


cleaned up the outside of the steel tube.
thing I found about the lathe chuck is that it ain't exactly centered. after lathing one end smooth n flat, I swap ends and it'd be off-center, suppose can only use one end for now.

IMAG4401.jpg


bored the inside of the steel tube to 60.01mm and the alloy bung just about slips in by 10mm (there's a very very slight taper probably from the bore tool poking so far out from the toolpost)

IMAG4402.jpg
IMAG4403.jpg


now with the insides supported, I can take tiny cuts getting so close to 60.2mm
maybe it was a good thing the alloy bung didn't go all the way cos I think the alloy was getting warm/expand & wobble slightly and causing the tip to cut too close and begin to create holes.
the rest of the steel tube not supported by the alloy bung was bout 60.25 - 60.30mm

IMAG4404.jpg


cut & file the ends off with a dremel

IMAG4405.jpg


and voila, the sleeve thickness ranges from 0.13 - 0.20mm, that's as close as I'll get tbh

IMAG4406.jpg


soon see if it fits
 
OP
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pollyp

pollyp

Club Member
to correct the lathe chuck off-center, I needed a really smooth, round, straight reference rod and the shafts from my old coilover dampers came in handy

IMAG4410.jpg


a quick jig to hold the dial indicator from my bore gauge kit.
the chuck is about 0.07-0.09mm offset and with the reading getting bigger further away from the chuck, it's also angled slightly off-axis.
I had to grind a small amount off the backing plate to give the chuck room to shift around, then with the chuck securing nuts loosened I nudged the chuck with a rubber hammer till the dial is 0.01-0.03mm offset. the accuracy is very dependant on how the 3-jaw chuck clamps onto the rod each time.

IMAG4412.jpg


the 2 x 14mm parting blade arrived but this cheapo quick-change post ain't made right. it only has a 1mm lip and doesn't clamp squarely. it's guaranteed to slip off dangerously under load

IMAG4414.jpg
IMAG4415.jpg


so figured I could setup the lathe like this, fit my dremel milling bit on the chuck and use it as a milling machine :cool:

IMAG4421.jpg
IMAG4422.jpg


now the blade is secured much safer

IMAG4420.jpg
IMAG4419.jpg


the lathe cross slide handle has alot of play when changing direction. I previously tried to remove this handle with a hammer to access the mechanism but was unsuccesful.
so this time made this simple puller which worked better.

IMAG4423.jpg


there's no bearing but just a simple lip. there's a 0.07mm play in the cavity (don't have any washer that thin) so I just sanded & sanded the steel face down till it's snug enough

IMAG4424.jpg
 
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pollyp

pollyp

Club Member
a project that's been taking me few days to resolve was my dads bike where the chain kept falling off the big front pedal sprocket when in low gear (offset between the large front & rear sprockets too large).

I lathed this shaft to hold the cogs from a rear derailer and use it as an idler gear to keep the chain moving straight to/from the pedal gear

IMAG4427.jpg


idler cogs mounted to a stiff L-bar bolted to the frame.
also notice I welded up a new pedal sprocket closer to the center to reduce the offset between front/rear gears
(welded the big sprocket onto an old steel cutting disc)

IMAG4426.jpg
IMAG4425.jpg


but this didn't work. the steep angle of the chain simply made it skip off the cogs, especially when changing down-gear and the chain rattles up/down.
also the sprocket wasn't welded perfectly straight & concentric on the flat disc.
so made these flanged idler wheels to hold the sides of the chain

IMAG4429.jpg
IMAG4430.jpg


this kinda worked (flange wasn't high enough to enclose the chain) but due to the oscillating shape of the chain on the smooth wheel, it vibrates too much and very noisy.

so rather than use this scrapheap welded off-center pedal sprocket, decided to use the original straight crank sprocket and rather than lathe & retap a new length of rod, I lathed a threaded rod to hold the cog

IMAG4431.jpg


the straight round pedal sprocket helped but the angled chain still skips off

IMAG4432.jpg
IMAG4433.jpg


instead of using wheels to guide the chain, I decided to fully enclose the chain with a tube so it has no chance of skipping off the pedal sprocket.
wanted to flare this tube to smoothly guide the chain from all angles, so made this cone forming tool

IMAG4434.jpg
IMAG4435.jpg


welded them to threaded rod for adjustments

IMAG4436.jpg


mounted to the L-bar, it now works soo well :cool:
other than the slight chatter of the chain running along the tubes, the chain no longer falls off

IMAG4437.jpg
IMAG4438.jpg
IMAG4439.jpg


christ that was quite a distraction and made a mess in the garage.
now I can begin fixing the loose driveshaft :rolleyes:
 
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pollyp

pollyp

Club Member
so I removed the driveshaft tday, the thin sleeve just "barely" slipped over the shaft. the outer dia is now 60.3mm
did it work? no

the hole seems to be tighter than 60.3mm looking at how the chamfered hole has bashed the front edge in, it doesn't fit :(

IMAG4441.jpg


so what size is the hole?
to test, I grabbed the pipe that I lathed precisely to 60mm outer dia and inserted into the LSD hole to check how much clearance there is.
it seems that the hole is tapered from the years of this driveshaft rattling about.
when fully inserted, the pipe only has a very tiny amount of slack but when it's 1/2 out, there's abit of play.

bobore.jpg


so the LSD bore is at fault, the driveshaft is fine n straight.

the driveshaft could've been lathed down to the dia of the splines at 24.7mm so the sleeve could be a thicker 0.625mm but that would get rid of the oiling grooves on the shaft, which I dunno how that'll affect lubrication.

really don't fancy taking the LSD out to get it machined either so I guess I'll just have to live with it :rolleyes:
 
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pollyp

pollyp

Club Member
just booked my ticket & 12:40 track time slot fot the Petrol & Pistons Show at Croft on 21/08/2016
http://petrolandpistons.co.uk/

have to learn I track I've never driven before.
hopefully Neil Jackson will be there in his white nismo k11 or silver lotus :cool:

If anyone is going, could pop by ;)
 
OP
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pollyp

pollyp

Club Member
checked the size of the LSD hole by lathing a tube diameter down till it fits.
found the inside is 60mm while the outside of the tapered hole is exactly 60.1mm

hole.jpg


lets dismantle the inner joint so I can use the inner shaft as reference for lathing the new piece. cut off the one-piece boot clip

IMAG4442.jpg


ew it's filled with this brown runny goo. wonder if I'll be alright using that dark grey CV grease I got from halfords

IMAG4443.jpg


the inner shaft has a nicely machined lip, gr8 for clamping on the lathe

IMAG4444.jpg


other than some little heat discolouration, ain't too bad inside

IMAG4445.jpg


machined a tube upto 59.92mm inner dia

IMAG4447.jpg


and it slips nicely over the 59.91mm shaft.
mount the assembly onto lathe, center it, then lathe the outer dia to precisely match the LSD bore :cool:

IMAG4448.jpg
 
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OP
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pollyp

pollyp

Club Member
centered via the machined oil seal surface nearest the sleeve within 0.025mm

IMAG4450.jpg


began shaving the sleeve outer dia down.
although the sleeve was bored to 59.92mm and just slid over the 59.91mm shaft, the sleeve would occasionally spin around whilst cutting which ruins the concentricity.
so to keep it still, just afew dabs of superglue helped

IMAG4451.jpg


lathed it down to 60.05mm (took abit too much on the last cut).
getting about as thin as kitchen foil with the oil grooves showing up and how it's crinkling

IMAG4452.jpg


the inner part might be too tight and the crinkles don't help, so I tried to split it off with a part tool, was worried it'll tear the thin sleeve so finished the cut with a craft blade

IMAG4453.jpg


completed sleeve

IMAG4455.jpg


fully inserted into LSD but there's still abit of rocking, perhaps the 60.05mm sleeve in the 60.1mm hole was still too loose? or maybe I should've left that crinkly inner section of the sleeve on?
meh it's better than nothing

IMAG4456.jpg


certainly snug enough from the scratch marks

IMAG4457.jpg


k reassemble & install the driveshafts tomorrow
 
OP
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pollyp

pollyp

Club Member
Water has got into your CV grease there...

Water? In the same way that mixing coolant & engine oil gives a choc milkshake look? Wonder how that happened cos the cv boot n clips look original n all intact n solidly secure.

I'll be ok using that grey cv grease?
 
Wonder how that happened cos the cv boot n clips look original n all intact n solidly secure.

Did you ever go through a reasonably deep puddle or ford?

There's air in the CV joint as well as grease, as the CV works it heats up and expands pushing some air out of the boot, immerse it in water and it suddenly cools the air contracts creating a suction, sucking in whatever is around it in the case of a puddle....water.

As a caver we'd get the same problem with supposedly waterproof headlamps...
 
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pollyp

pollyp

Club Member
Did you ever go through a reasonably deep puddle or ford?

There's air in the CV joint as well as grease, as the CV works it heats up and expands pushing some air out of the boot, immerse it in water and it suddenly cools the air contracts creating a suction, sucking in whatever is around it in the case of a puddle....water.

As a caver we'd get the same problem with supposedly waterproof headlamps...

Nice explanation. The last time I drove through a deep ford was I think 2012 during heavy rain n poor country road drainage, enough to make the engine misfire for few secs.
I'll repack it with grey grease n hope for the best.
 
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pollyp

pollyp

Club Member
I wasn't satisfied that the driveshaft was only half snug, I didn't go through all this disassembly just to do it again later, so lets do this again properly :rolleyes:

don't have any steel pipes that's 25-27mm dia, the only one's I found close are the fork stems off bicycles, so had to sacrifice this road bike frame that I'll never use cos it's too small

IMAG4459.jpg


bored the steel tube to exactly 59.91mm

IMAG4460.jpg


this time it's such a close tolerance fit that I had to hammer the sleeve on, this'll help secure the sleeve on the shaft while I lathe it

IMAG4461.jpg


centered the shaft

IMAG4462.jpg


now the long process of trimming the diameter down bit by bit and got close to 60.11mm outer & 60.05mm inner.
had to change the carbide tips few times to cut accurately and stop it vibrating.
test fit in the LSD and it's real snug with zero play :cool:

IMAG4464.jpg


cleaned as much of the old goo off

IMAG4465.jpg


and repacked with grey Comma lithium moly CV grease

IMAG4466.jpg


shafts installed

IMAG4467.jpg



and the result?
went to a high speed right turn on the country road where I usually hear it wobble about and this time it's quiet :D there's only the very slightest wobble per rotation but I believe that's the outer CV which has abit of play.
so that's fixed now :)
 
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pollyp

pollyp

Club Member
this micro switch for the ECU speed sensor stopped working

IMAG4470.jpg


so replaced with a proper switch and located here for ease of access and with the terminals away from the metal column

IMAG4471.jpg
IMAG4472.jpg


works now

IMAG4473.jpg
 
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