PollyMobiles Rebuild

[pollyp]

after such a long hard weekend drive, gave kasandra a much needed oil change.
little bits in the plug

oil very dark & dirty

all fresh now

 

[pollyp]

collected an old lower arm from a friend

removed the c-clip

hammered the ball joint out

wirebrushed and it measured 35.05 - 35.10mm dia.
now I have the data for choosing which spherical bearing to use.

 

[pollyp]

ordered a pair of GE12AW steel-teflon lined spherical bearings and some 50mm steel rod to machine

after a 1000mile return trip down to japfest, the catchcan only caught 96ml!
something really ain't working right so gotta check that out. maybe machine the container out of more conductive Alu/steel

 

[John_D]

ordered a pair of GE12AW steel-teflon lined spherical bearings and some 50mm steel rod to machine

View attachment 53873

after a 1000mile return trip down to japfest, the catchcan only caught 96ml!
something really ain't working right so gotta check that out. maybe machine the container out of more conductive Alu/steel

View attachment 53872

If you are machining critical suspension components yourself Paul you need a suitable high tensile steel ! See HERE. The sort of easy machinable mild steel that you probably have got is NOT suitable!
Critical steering/suspension components are usually cold formed/rolled, which imparts extra strength to the component, forming the grain structure of the material within the shape of the component, not by turning/dieing, which cuts through the grain structure, weakening the part. Also strength critical parts are usually heat treated to specific hardness/toughness parameters after the forming process....(I was, for the last 11 years of my working life, prior to retirement, a designer in the automotive fastener industry and amongst other things, spent many hours doing tensile tests on batches of components, failing quite a few that had been incorrectly heat treated or manufactured by far eastern sub-contractors from inferior grades of steel....)

 

[pollyp]

If you are machining critical suspension components yourself Paul you need a suitable high tensile steel ! See HERE. The sort of easy machinable mild steel that you probably have got is NOT suitable!
Critical steering/suspension components are usually cold formed/rolled, which imparts extra strength to the component, forming the grain structure of the material within the shape of the component, not by turning/dieing, which cuts through the grain structure, weakening the part. Also strength critical parts are usually heat treated to specific hardness/toughness parameters after the forming process....(I was, for the last 11 years of my working life, prior to retirement, a designer in the automotive fastener industry and amongst other things, spent many hours doing tensile tests on batches of components, failing quite a few that had been incorrectly heat treated or manufactured by far eastern sub-contractors from inferior grades of steel....)

i already just brought some EN1A bright mild steel off ebay
http://www.ebay.co.uk/itm/291541838...49&var=590599586376&ssPageName=STRK:MEBIDX:IT

what grade & source dya recommend for machining & welding onto the lower arms?

 

[John_D]

i already just brought some EN1A bright mild steel off ebay
http://www.ebay.co.uk/itm/291541838286?_trksid=p2060353.m2749.l2649&var=590599586376&ssPageName=STRK:MEBIDX:IT

what grade & source dya recommend for machining & welding onto the lower arms?

I wouldn't, too many unknowns. Recipe for disaster in my opinion, it's one thing to make and fit spacing parts, securing original components with like, but longer, high tensile bolts, but to make totally new critical components without a great deal of knowledge about metallurgy/material properties and the stresses that the components will be subjected to is bordering on insanity!

 

[fuzzy-hair-man]

I thought the ball joints didn't come out!

I'd go back to looking if there's any other ball joints that use the same taper, I was thinking if the nut bolting to the hub is the same size the taper is more likely to be the same as well. Trouble is searching on parts 4 u lists a heap of models using the same nut but I'm not sure how to work out if they are used on a ball joint. I can't remember is it a castellated nut?

 

[pollyp]

I wouldn't, too many unknowns. Recipe for disaster in my opinion, it's one thing to make and fit spacing parts, securing original components with like, but longer, high tensile bolts, but to make totally new critical components without a great deal of knowledge about metallurgy/material properties and the stresses that the components will be subjected to is bordering on insanity!

High tensile bolts will be used to clamp it together.
The spherical bearings will be housed within the original arm bore so lateral loads are no prob.
the machined upper & lower cups with circlip will be welded onto the arms to keep the bearings secured vertically within the arm.

 

[pollyp]

I thought the ball joints didn't come out!

I'd go back to looking if there's any other ball joints that use the same taper, I was thinking if the nut bolting to the hub is the same size the taper is more likely to be the same as well. Trouble is searching on parts 4 u lists a heap of models using the same nut but I'm not sure how to work out if they are used on a ball joint. I can't remember is it a castellated nut?

highly doubt a 35mm dia lower ball joint with extended tapered rod exists for these arms or economical.
engineering my own is far easier, cheaper & faster.
some use castellated nuts, some use lock nuts.

 

[pollyp]

the 50 x 500mm steel rod arrived and jeez it weighs a ton

ordered some GE12AW which I thought from the pics were full spherical bearings but damnit turns out to be half-spherical bearings so will have to return em

gonna order some GEH17C which appears & measures up to be a fully spherical steel/PTFE bearing

 

[pollyp]

the GEH17C bearing & inner circlip arrived

looks like a steel outer casing with a sintered bronze & PTFE lining. swivels very smoothly

it slots into the lower arm hole like a glove

a bonus is that the 12mm high bearing case sits just about flush with the original bore on the arm

so I simply just need to machine some retaining cups at both ends and the circlip sits' like this

the original ball joint sits like this with 32 deg of swivel

here's the new arrangement.
- GEH17C spherical bearing (red/green) sits inside the existing hole on the lower arm (white),
- the upper retaining cup (yellow) is welded onto the lower arm. it transfered upward bump forces from the bearing to the arm and holds the rubber dust cover/boot.
- the lower retaining cup (turquoise) is welded under the arm and keeps the bearing retained via the circlip (grey) to transfer rebound forces to the arm.
- extension collar (blue) lowers the ball joint by 40mm and transfers vertical & lateral forces from the hub to the bearing.
- the lower collar washer (yellow) and extension collar (blue) clamps onto the spherical bearing.
- high tensile M12 x 120mm bolt (orange) keeps the whole assembly clamped tight onto the hub and transfers the bump forces from the hub to the bearing.

the bearing also has a much wider 38 deg swivel range

now I need to find a suitable CV boot to cover the joint

 

[John_D]

the GEH17C bearing & inner circlip arrived

View attachment 53890

looks like a steel outer casing with a sintered bronze & PTFE lining. swivels very smoothly

View attachment 53891

it slots into the lower arm hole like a glove

View attachment 53892

a bonus is that the 12mm high bearing case sits just about flush with the original bore on the arm

View attachment 53893

so I simply just need to machine some retaining cups at both ends and the circlip sits' like this

View attachment 53889

the original ball joint sits like this with 24 deg of swivel

View attachment 53898 View attachment 53897

here's the new arrangement.
- GEH17C spherical bearing (red/green) sits inside the existing hole on the lower arm (white),
- the upper retaining cup (yellow) is welded onto the lower arm. it transfered upward bump forces from the bearing to the arm and holds the rubber dust cover/boot.
- the lower retaining cup (turquoise) is welded under the arm and keeps the bearing retained via the circlip (grey) to transfer rebound forces to the arm.
- extension collar (blue) lowers the ball joint by 40mm and transfers vertical & lateral forces from the hub to the bearing.
- the lower collar washer (yellow) and extension collar (blue) clamps onto the spherical bearing.
- high tensile M12 x 120mm bolt (orange) keeps the whole assembly clamped tight onto the hub and transfers the bump forces from the hub to the bearing.

View attachment 53899 View attachment 53900 View attachment 53895 View attachment 53894

the bearing also has a much wider 38 deg swivel range

View attachment 53896

now I need to find a suitable CV boot to cover the joint

Paul, how are you filling the space around the clamping bolt, left by the tapered ball joint? At the very least you will need a hardened, tapered sleeve slid over the bolt... I do hope that your welding skills are good enough to attach the top retaining collar to the lower suspension arm, a failure there would be catastrophic!

 

[pollyp]

Paul, how are you filling the space around the clamping bolt, left by the tapered ball joint? At the very least you will need a hardened, tapered sleeve slid over the bolt... I do hope that your welding skills are good enough to attach the top retaining collar to the lower suspension arm, a failure there would be catastrophic!

updated the design, I'll be using a beefier M16 bolt so the head covers more of the ball bearing edge and I'll be drilling the hub with a straight 16mm bit to fit snug against the bolt. my welding is fine, I've rewelded these arms before and zero problems after so many trackdays.

 

[John_D]

updated the design, I'll be using a beefier M16 bolt so the head covers more of the ball bearing edge and I'll be drilling the hub with a straight 16mm bit to fit snug against the bolt. my welding is fine, I've rewelded these arms before and zero problems after so many trackdays.

View attachment 53901

Better Idea Paul, though don't just drill out the arm with a 16mm drill bit, you need a really snug (slide) fit with the bolt shank, so better to drill undersize and ream the hole for an exact fit to the bolt.
As well as the top rubber cover to the joint you will also need a cover for the underside to keep dirt out of the ball joint.........

 

[pollyp]

Better Idea Paul, though don't just drill out the arm with a 16mm drill bit, you need a really snug (slide) fit with the bolt shank, so better to drill undersize and ream the hole for an exact fit to the bolt.
As well as the top rubber cover to the joint you will also need a cover for the underside to keep dirt out of the ball joint.........

yup working on that

 

[pollyp]

Modelled the geometry before & after the extension.

Full Droop
When fully drooped, both ball joints are swivelled right at their limits.

I would've preferred to pie-cut & bend the angle of the bearing mount / arm from 12deg to 20deg so the bolt head won't strike the casing but I don't wanna further weaken the arm tbh.

Static Ride Height
At normal ride height, notice how the standard ball joint is pointing above the chassis mount and lowering the roll center well away from the CoG.

Extending the ball joint by 40mm raises the roll center alot closer the CoG so it's less likely to roll as much during corner entry.
the edge of the arm is quite close to the red hot brake discs so gotta be careful how I mount the rubber dust boot.

Bump Stop
When the front end is maxed out on the bump stops during intense braking or cornering, jeesus look at how far the standard ball joint points up and no surprise why it really wants to roll over all the time

The extended ball joint when at bump stop is barely above the chassis mount so the roll center is massively better than before

Standard Ball Joint Bump Travel
During the bump travel on the current standard ball joints, the awful geometry tucks the wheels inwards alot which induces +ve camber wearing out the outer shoulders (especially with bad roll center), uneven bump steer, and points the steering toe-in during braking or diving.

Extended Ball Joint Bump Travel
With extended ball joints, the geometry stays perfectly vertical so hopefully there's less bump steer, consistant wheel alignment toe, even tyre wear, less body roll, flatter tyre patch and better front end grip as a result

 

[SuperUno]

Wrap exhaust heat wrap around the ball joint, and use a metal 'zip tie' to hold it in place.

 

[pollyp]

Wrap exhaust heat wrap around the ball joint, and use a metal 'zip tie' to hold it in place.

currently looking for a steering rack gaiter or fork arm gaiter or just a straight bit of rubber tube that's 36mm inner-dia to fit the two ends.
exhaust wrap is a good idea but think it may unravel apart & let water in cos the hub swivels round, unless you mean let the top bit swivel loose.

 

[SuperUno]

I was meaning you use the heat wrap to protect whatever rubber boot/gaiter/tube you use.

 

[pollyp]

I was meaning you use the heat wrap to protect whatever rubber boot/gaiter/tube you use.

ah yes good idea

 

[pollyp]

ordered a 15.5mm drill bit and a 16mm straight flute hand reamer tool

found the nearest fitting ball joint dust cover

for the underside I'll just snug this plastic pipe cap over the bearing housing

it'll be like this

 

[pollyp]

the 15.5mm drill bit, 16mm reamer, ball joint covers and end caps arrived. just gotta prep some lathe tools and practice with the welder before beginning

the wideband has recently been struggling to warmup & read correctly during cold starts (takes at least 3 restart attempts). it looks abit sooty, maybe clogging up

so good time to replace it. reads much better, faster and doesn't randomly lean-out as much during idle

 

[pollyp]

got some shiny new open wheel nut

removed the rusty old ones

and fitted the new ones

cannot believe the front wheels have survived 7 years of daily & track stress held by only half the nut threads?
I should really fit the longer studs at the front too

 

[John_D]

You are pushing your luck there with those wheel nuts Paul! (especially if the new chrome, after market, ones are not to the same hi tensile strength as the old OEM ones...ever heard of 'hydrogen embrittlement?)

 

[pollyp]

You are pushing your luck there with those wheel nuts Paul! (especially if the new chrome, after market, ones are not to the same hi tensile strength as the old OEM ones...ever heard of 'hydrogen embrittlement?)

I've used steel nuts from ebay for years & many trackdays with zero issues

 

[John_D]

I've used steel nuts from ebay for years & many trackdays with zero issues

Your choice Paul, I don't believe in taking chances on safety issues......
With full thread engagement the chrome after market nuts are probably perfectly OK, but with the minimal thread engagement on your front wheel studs you are taking a risk that could easily be be averted by fitting longer studs.....

 

[yorkiesteve]

But I thought you had fitted longer hub studs Paul ?

 

[pollyp]

Your choice Paul, I don't believe in taking chances on safety issues......
With full thread engagement the chrome after market nuts are probably perfectly OK, but with the minimal thread engagement on your front wheel studs you are taking a risk that could easily be be averted by fitting longer studs.....

ever since I fitted these alloys 7 yrs ago and pushed them hard on track it's always been with these aftermarket nuts threaded in by bout 20mm and it held up perfectly fine so they're well up to the task.
but yeah now that I know the fronts are only 1/2 way in, I'll upgrade the front studs too.

 

[pollyp]

But I thought you had fitted longer hub studs Paul ?

only extended the rear hub after I fitted the 8mm spacer.
now that I realise the front nuts only 1/2 way in, I'll fit the remaining studs on the front hubs too in near future

 

[John_D]

ever since I fitted these alloys 7 yrs ago and pushed them hard on track it's always been with these aftermarket nuts threaded in by bout 20mm and it held up perfectly fine so they're well up to the task.
but yeah now that I know the fronts are only 1/2 way in, I'll upgrade the front studs too.

I would say that you have been very lucky Paul, there are 'after market nuts' and there are 'after market nuts'!
With the OEM wheel nuts you know that
a) they are made from the correct grade of steel every time and
b) almost certainly cold headed in the same factory as the ones originally fitted to the car.
With after market ones you do not have this . Ones bought one day might well be correctly specced both in material and manufacturing process (though unlikely if made to a price, in smaller quantities), while the next day, from a different supplier, they could well have been made from an inferior grade of steel and die threaded in some back street workshop in Pakistan. Less critical on a standard road car with full thread engagement, being pottered around by some old lady, but that is far from the case with your car
Do not just assume that the after market nuts that you are fitting will hold up the same way as the ones previously on the car. The fact that they are plated already potentially modifies the steel structure, do research on 'hydrogen embrittlement and chrome plating'.
In the earlier days of Formula Ford racing there were some catastrophic accidents caused by failures of front wishbones that had been chrome plated to 'look pretty', where non plated ones had never failed before.........

 

[frank]

even if they are only mild steel nuts, they will still be stronger than alloy nuts tho john, and there are plenty of alloy ones sold

 

[John_D]

even if they are only mild steel nuts, they will still be stronger than alloy nuts tho john, and there are plenty of alloy ones sold

A useful guide HERE Paul and some horror stories about aluminium wheel nuts HERE .......... Though I doubt that mild steel ones would fare much better.....

 

[pollyp]

thanks for the link john, should be a good read. tis a relief that after all this time, those steel nuts haven't stripped a thread during a high-G high-speed corner, especially at nurburgring but safe to say I'll be extending the studs for full thread engagement to be sure they'll hold

ooh I've never ever trusted those flimsey aluminium nuts, especially cheapo ebay imports. maybe alright for just a static trailer-queen show car purely for looks but never trusted on british roads or track.

 

[pollyp]

made the lower retaining cups

fits like this

stick welding in that tight gap will be tricky but achievable with practice. alternatively I'm thinking of cutting the obstructing sides off, so I have better access to weld the cup onto the arm, then weld the side piece back onto the arm

made the upper retaining cup

the rubber dust boot & bottom cover fits like this.

awaiting the new fasteners before machining the extension bits

 

[John_D]

I wouldn't cut the lip off and re-weld it Paul, most of the strength comes from the forming process.........

 

[pollyp]

I wouldn't cut the lip off and re-weld it Paul, most of the strength comes from the forming process.........

ok I'll weld in that tight gap there

 

[pollyp]

machined the 24mm socket down to clear the hub

made a precise thin sleeve to go between the 16mm bolt and 17mm bearing hole and slips in like a glove

I ordered five M16x130mm bolts from ebay last thurs 18/5/17 (expected 23rd) but it didn't arrive till 25/5/17 and holding everything up so I ended up buying some locally for a premium.
turns out the 5 ebay bolts on the left has a plain shank of 76mm whereas the 3 local bolts I just got tday on the right has a longer shank of 82mm, so will be returning these ebay bolts.
actually the staight shank bit barely reaches the hub hole so I'm gonna replace em with longer 140mm bolts.

little spacer to lift the bolt head away from the circlip at the sides

begin machining the tapered extension collar

I really hate parting-off on this machine, the tip snatches afew times

so I just hacksaw it off and finish the end on the lathe

one end complete

clears the upper retainer as expected

and the bottom retainer

dust cover clears the components fine

 

[pollyp]

got some M16 x 140mm bolts

much better with 14mm of smooth shank above the extension to slot into the hub hole

it was soo hot today

 

[pollyp]

machined the 2nd extension

all the bits ready to install

 

[SuperUno]

What is the idea of the cone shape on the extension? I understand you need it to keep the movement, but why not have it the same dia. all the way up?

 

[pollyp]

What is the idea of the cone shape on the extension? I understand you need it to keep the movement, but why not have it the same dia. all the way up?

it's for strength & stiffness.
the lower ball joint is gonna be extended 40mm further away from the hub so there'll be massive lateral bending forces on the extension shafts from heavy braking, cornering and acceleration as well as vertical bump/rebound along the shaft. so I'll need as much stiffness as possible.

if it was just a straight 21mm diameter extension, it'll only provide a limited amount of stiffness.

since the spherical bearing has a 21mm end and the hub upright has a 50mm wide base, I taper the extension to provide maximum stiffness between the points (similar to corner gussets), reducing some weight, not foul with surrounding areas throughout the swinging travel and have no sharp undercut features to form any cracks.

the 15mm straight bit is to clear the upper retaining cup which holds the rubber dust cover.

 

[pollyp]

catchcan only got 41ml after 343 miles. either it's not cold enough to condense or the plumbing is blocked or there's less oil vapour? needs checking out

time to removed the suspension

the front pads are wearing evenly at half way down to 13.5mm

arm & hubs removed. the LH wheel bearing feels abit loose which may explain the rumbling during fast right turns, may as well replace it next week while its all apart.

dismantled

the LH arm is getting abit rusty

thankfully the spare arm I got from sophie (bottom) is abit fresher and better to weld

the machined socket just about clears the hub

the extension will fit nicely

 

[pollyp]

the msc server being abit glitchy recently?
occasionally since thursday the "my profile/my content" link shows up as error. and now I can't upload any images

 

[pollyp]

practice & setting up the welder on the rusty arm. stick welder was too inconsistant, uneven, hard to control and sometimes blowing holes during long runs as heat builds.
so dialed in the MIG welder instead and it does a much better job, good penetration, consistant & even appearance with little clean up, especially handy for the tight areas.

reinforced the rear peg of the spare arm

carefully welded the retaining cups of the left arm

and right arm

both arms welded up

 

[John_D]

practice & setting up the welder on the rusty arm. stick welder was too inconsistant, uneven, hard to control and sometimes blowing holes during long runs as heat builds.
so dialed in the MIG welder instead and it does a much better job, good penetration, consistant & even appearance with little clean up, especially handy for the tight areas.

View attachment 54008

reinforced the rear peg of the spare arm

View attachment 54009

carefully welded the retaining cups of the left arm

View attachment 54011

and right arm

View attachment 54012

both arms welded up

View attachment 54010

Nice job with the MIG welding Paul

 

[pollyp]

Nice job with the MIG welding Paul

thanks so much john for ur input & compliment
such a relief that the MIG welded so nicely and seeing the design coming together is fab

 

[pollyp]

needed to remove the front rubber bush on the spare arm. instead of tediously drilling alot of holes in the rubber and tearing it out, I made this hole cutter

to cut through all the rubber

and removed the outer sleeve. now I can fit the PU bushing

arms repainted

 

[pollyp]

drilled & reamed the hub till the bolt fits snug

test fit the assembly. the top of the bolt & nut just misses the driveshaft.

and enough clearance between the bolt & wheel

 

[pollyp]

machined the new studs down to length

Received new wheel bearing

Hammered the hub off

A slight ding on the hub from a previous removal

There's the cause of the right turn whirring noise, same defect as on the rear hubs

Tried removing the outer race but I don't have any round steel large enough and it's pretty stuck so will take to a shop

 

[John_D]

machined the new studs down to length

Received new wheel bearing

Hammered the hub off

A slight ding on the hub from a previous removal

There's the cause of the right turn whirring noise, same defect as on the rear hubs

Tried removing the outer race but I don't have any round steel large enough and it's pretty stuck so will take to a shop

Pictures not showing Paul