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Bullet2012
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Weee, do you have a pilots license or should we inform the civil aviation mob ? 
PhillipM
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Don't ask. This is completely normal and 100% not a scary lash up, honest. Machinists look away now. Health and Safety people should delete the entire bookmark.
But at least they're back flat now:
So these discs warped when they were hot zinc plated, and the plan was originally to heat cycle them gently to get the stress out of them, then take them off the car and grind them flat before the car got used in anger.
That obviously never happened and because they were getting hot spots they got worse and worse lately - the things had more bow than a pringle in them.
Ground them back flat in a seriously Heath Robinson manner for now, just to get the brakes back, as it's been knocking the brake pads back and needing the pedal double pumping at higher speeds - they were half a mm out of true (discs should generally be under 0.05mm)
Obviously not good, so this is a temporary fix for now, and then we'll get some more cut either out of cast iron plate if we can manage it (which I originally wanted but our parts are so small you have to wait until somewhere has some spare offcuts basically) - or probably have them done out of 10mm thick plate next time, stress relieve them and then machine them back true to 8mm thick - I've already got a jig for it as we made one to do the discs originally before we got carried away and forgot
But at least they're back flat now:
So these discs warped when they were hot zinc plated, and the plan was originally to heat cycle them gently to get the stress out of them, then take them off the car and grind them flat before the car got used in anger.
That obviously never happened and because they were getting hot spots they got worse and worse lately - the things had more bow than a pringle in them.
Ground them back flat in a seriously Heath Robinson manner for now, just to get the brakes back, as it's been knocking the brake pads back and needing the pedal double pumping at higher speeds - they were half a mm out of true (discs should generally be under 0.05mm)
Obviously not good, so this is a temporary fix for now, and then we'll get some more cut either out of cast iron plate if we can manage it (which I originally wanted but our parts are so small you have to wait until somewhere has some spare offcuts basically) - or probably have them done out of 10mm thick plate next time, stress relieve them and then machine them back true to 8mm thick - I've already got a jig for it as we made one to do the discs originally before we got carried away and forgot
PhillipM
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Well after all that work, one of the wheel bearings picked up, welded itself to the nut, unscrewed it, the hub slid off and the disc hit the caliper so now the disc is both bent and covered in melted aluminium. All that work sorting them out too...
I swear this car is cursed:
But we got a few decent pictures:
after some hours of work, we've traced the problem, which is 90% of the battle - it's no good fixing something if it's just going to do it again - but it looks like the spindle cinch nut had fatigued, and managed to vibrate loose, despite the cinch bolt being tight and loctited - most probably from material fatigue on the aluminium.
Then it vibrated looser and looser until the locking/tabbed washer finally dropped out of it's slot and then that allowed the bearing to spin the nut off, which explains the whole lot suddenly falling off on the last 3-4 corners - and why the right side is fine, the right side would tighten itself while driving from the rotation, while the left loosens. And also why the thread is only damaged on the end of the spindle and was fine in the nut.
Which also means it's a fairly easy fix of switching them out for some stronger steel castellated nuts and roll pins to secure them, and not some sort of issue with the front hub/spindle/bearing assembly we'd previously got away with.
Unfortunately, because of the damage caused when it did come off, that means we need to machine and weld on a new spindle, sort new bearings, fettle a little bit of damage to the brake mounting bells and make new brake discs...so it's not all smooth sailing.
Onwards with the machine work I guess...
I swear this car is cursed:
But we got a few decent pictures:
after some hours of work, we've traced the problem, which is 90% of the battle - it's no good fixing something if it's just going to do it again - but it looks like the spindle cinch nut had fatigued, and managed to vibrate loose, despite the cinch bolt being tight and loctited - most probably from material fatigue on the aluminium.
Then it vibrated looser and looser until the locking/tabbed washer finally dropped out of it's slot and then that allowed the bearing to spin the nut off, which explains the whole lot suddenly falling off on the last 3-4 corners - and why the right side is fine, the right side would tighten itself while driving from the rotation, while the left loosens. And also why the thread is only damaged on the end of the spindle and was fine in the nut.
Which also means it's a fairly easy fix of switching them out for some stronger steel castellated nuts and roll pins to secure them, and not some sort of issue with the front hub/spindle/bearing assembly we'd previously got away with.
Unfortunately, because of the damage caused when it did come off, that means we need to machine and weld on a new spindle, sort new bearings, fettle a little bit of damage to the brake mounting bells and make new brake discs...so it's not all smooth sailing.
Onwards with the machine work I guess...
PhillipM
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Okay, we had the new spindles made, jigged and welded onto the uprights (buttered with 309L on the TIG first and then a mig pass over the top to finish) , spare hub fitted and 2 more machined up, new brake bell and finally, 4 new brakes in 10mm material cut, rough machined, annealed in a pizza oven, and finish ground. Everything is back together and the brakes feel a lot better. I think I'm gonna make some changes to the calipers a bit though later on.
Anyway, I was over in Germany in August, so Ed got the car back together ready for a race at Tiverton while I was swanning around:
[youtube]
(apologies for the poor video, I didn't film it, don't blame me )
As you can see definately bedding them in gently....
Unfortunately, due to heavy rain, after a 5 hour trip , the event got called off, as some area's of the course are pretty much impassable even being careful with jacked up course cars hooked together on winches, never mind the racers. So it was a long drive home for him!
Since that round didn't happen, this weekend there were two rounds to catch up, one on Saturday, one on Sunday
Unfortunately I was stuck at home with a very sick dog (in fact she's passed away unfortunately) so Eddy again took his missus as a passenger for the weekend and headed down with some friends for support.
Car seemed pretty good and it ended up 7th in yesterdays event and 8th today - out of a LOT of cars as the event was booked solid to the limit - and 40-50 seconds per stage faster than the next nearest 2wd competitor.
Given the amount of 400 horsepower 4wd cars there, pretty happy.
It also managed the 3rd fastest stage time of the event, which is promising...
Anyway, I was over in Germany in August, so Ed got the car back together ready for a race at Tiverton while I was swanning around:
[youtube]
(apologies for the poor video, I didn't film it, don't blame me
)As you can see definately bedding them in gently....
Unfortunately, due to heavy rain, after a 5 hour trip , the event got called off, as some area's of the course are pretty much impassable even being careful with jacked up course cars hooked together on winches, never mind the racers. So it was a long drive home for him!
Since that round didn't happen, this weekend there were two rounds to catch up, one on Saturday, one on Sunday
Unfortunately I was stuck at home with a very sick dog (in fact she's passed away unfortunately) so Eddy again took his missus as a passenger for the weekend and headed down with some friends for support.
Car seemed pretty good and it ended up 7th in yesterdays event and 8th today - out of a LOT of cars as the event was booked solid to the limit - and 40-50 seconds per stage faster than the next nearest 2wd competitor.
Given the amount of 400 horsepower 4wd cars there, pretty happy.
It also managed the 3rd fastest stage time of the event, which is promising...
Shed engineering, got to love it...Don't ask. This is completely normal and 100% not a scary lash up, honest. Machinists look away now. Health and Safety people should delete the entire bookmark.
But at least they're back flat now:
So these discs warped when they were hot zinc plated, and the plan was originally to heat cycle them gently to get the stress out of them, then take them off the car and grind them flat before the car got used in anger.
That obviously never happened and because they were getting hot spots they got worse and worse lately - the things had more bow than a pringle in them.
Ground them back flat in a seriously Heath Robinson manner for now, just to get the brakes back, as it's been knocking the brake pads back and needing the pedal double pumping at higher speeds - they were half a mm out of true (discs should generally be under 0.05mm)
Obviously not good, so this is a temporary fix for now, and then we'll get some more cut either out of cast iron plate if we can manage it (which I originally wanted but our parts are so small you have to wait until somewhere has some spare offcuts basically) - or probably have them done out of 10mm thick plate next time, stress relieve them and then machine them back true to 8mm thick - I've already got a jig for it as we made one to do the discs originally before we got carried away and forgot
Bullet2012
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- 238 855 miles from the moon
Does it ever have all four wheels on the ground ? 
Bullet2012
Member
- Messages
- 5,126
- Location
- 238 855 miles from the moon
Awesome
Don't ask. This is completely normal and 100% not a scary lash up, honest. Machinists look away now. Health and Safety people should delete the entire bookmark.
But at least they're back flat now:
So these discs warped when they were hot zinc plated, and the plan was originally to heat cycle them gently to get the stress out of them, then take them off the car and grind them flat before the car got used in anger.
That obviously never happened and because they were getting hot spots they got worse and worse lately - the things had more bow than a pringle in them.
Ground them back flat in a seriously Heath Robinson manner for now, just to get the brakes back, as it's been knocking the brake pads back and needing the pedal double pumping at higher speeds - they were half a mm out of true (discs should generally be under 0.05mm)
Obviously not good, so this is a temporary fix for now, and then we'll get some more cut either out of cast iron plate if we can manage it (which I originally wanted but our parts are so small you have to wait until somewhere has some spare offcuts basically) - or probably have them done out of 10mm thick plate next time, stress relieve them and then machine them back true to 8mm thick - I've already got a jig for it as we made one to do the discs originally before we got carried away and forgot
I have to ask, why on earth would anyone hot zinc plate a brake disc?
PhillipM
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There was a bunch of stuff on the side to take, and Eddy decided they'd look nice shiny too and added 'em to the box.... don't ask.
They would have warped anyway from the heat cycling being machined from steel, the point was more to let them heat cycle a few times and then take them off and machine them flat. Which we never got around to.
But I actually often zinc plate cast iron brake discs - why do you think all those 'performance' discs from the likes of EBC, etc, are gold
They would have warped anyway from the heat cycling being machined from steel, the point was more to let them heat cycle a few times and then take them off and machine them flat. Which we never got around to.
But I actually often zinc plate cast iron brake discs - why do you think all those 'performance' discs from the likes of EBC, etc, are gold
PhillipM
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Okay, winter plan #1 is in progress, build up that new gearbox we just got hold of with the short ratio 3rd and 4th gear that's still on the shelf from like, 10 years ago, that should stop the car ending up out of vtec on a short shift/early shift on the bumpy stuff.
Slight problem. I need to hand file every single synchro tooth dog, all these little ones around the outside, for both gear pairs. Wish me luck...
Slight problem. I need to hand file every single synchro tooth dog, all these little ones around the outside, for both gear pairs. Wish me luck...
