Step by Silky Step

[chrism]

Now that rear hub mod is such a good idea! Those front discs are so easy to get hold of (and the price is sooo...much better )

" Rear Daewoo hubs were turned down to suit 236mm x 41mm x 12.6mm disks"

So, these are Daewoo hubs with the face machined down? What Daewoo did they come from? That seems a really brilliant way of replacing discs since the original parts sing from the 'have rare prices' song-sheet...

[RonR]

The Daewoo hubs are from the Espero, Lanos, Nexia, Nubira plus I think a few of the 1980s Vauxhall/Opel range had them, which is where Lotus found the stub axles in the GM parts bin. Why they didn't go the whole hog and fit the hubs and disks as well I can't begin to fathom.

The circumference has to be machined down to the same dimensions as the old Bob Brown hubs, plus a new retaining screw hole drilled, tapped and countersunk. Once done it's just plug & play with the disks. I'll put up something with the dimensions later....

Edit: Just remembered - the stub axles were from cars with rear drum brakes, but it's such a huge coincidence that these disks and hubs ape the one-piece disks & hubs in size, offset and thickness.

[chrism]

Brill! I reckon loads of us will thank you for that info

[Tuga2112]

The Daewoo hubs are from the Espero, Lanos, Nexia, Nubira plus I think a few of the 1980s Vauxhall/Opel range had them, which is where Lotus found the stub axles in the GM parts bin. Why they didn't go the whole hog and fit the hubs and disks as well I can't begin to fathom.

The circumference has to be machined down to the same dimensions as the old Bob Brown hubs, plus a new retaining screw hole drilled, tapped and countersunk. Once done it's just plug & play with the disks. I'll put up something with the dimensions later....

Edit: Just remembered - the stub axles were from cars with rear drum brakes, but it's such a huge coincidence that these disks and hubs ape the one-piece disks & hubs in size, offset and thickness.

sounds like there is business there for someone with a metal lathe... ive been tempted before, but the bottom line is that there's just not enough owners interested in the cost of the upgrade to make it pay off the investment. (ignoring the many hours needed to learn to operate the machine)

[RonR]

I have another iron in the fire for the rear hubs & brakes - coming later.

Anyway, the latest on Silky:

Almost there...

[Tuga2112]

I have another iron in the fire for the rear hubs & brakes - coming later.

Anyway, the latest on Silky:

suspension+brakes.jpg

looking forward for the news.

Im going to have a chat with pinky about this topic soon. see if there is some way i can help, under the assumption that these hubs do need little modification in order to be a viable solution.

[RonR]

Small update on the rear hub situation:

After fitting to the car I found there was a problem with disk run-out. More investigation needs to be done to work out why this happened.
Possible culprits:
1. The hubs were originally made for a drum brake set-up - drum brakes work in the vertical plane whereas disk brakes work in the horizontal, so the mounting face didn't have to be as accurate as for a disk brake.
2. These particular hubs were just not made that accurately, they were pattern parts rather than original GM, so that might be the case.
3. Something went wrong with the machining process, though I can't see how that would affect run-out as only the outer edge of the hub was altered.

Plan B is to use a slightly relieved rear upright with a more modern non-adjustable disk braked Astra rear Stub axle/Bearing/Hub and Disk. This arrangement gives a disk location about 1mm further in and the disk is only 10mm thick. The calipers fit and work fine, BUT the disk thickness at 10mm is around 2.5mm thinner than the Lotus one (adding lightness?) so I'll have to keep an eye on Pad wear.

Ideally I'd like to fit Honda rear calipers a la JamieN, which were designed for 10mm thick disks and have a handbrake with a more reliable self-adjusting mechanism. A caliper hanger needs to be designed and fabricated for these, so that's one for the future.

[Tuga2112]

Small update on the rear hub situation:

After fitting to the car I found there was a problem with disk run-out. More investigation needs to be done to work out why this happened.
Possible culprits:
1. The hubs were originally made for a drum brake set-up - drum brakes work in the vertical plane whereas disk brakes work in the horizontal, so the mounting face didn't have to be as accurate as for a disk brake.
2. These particular hubs were just not made that accurately, they were pattern parts rather than original GM, so that might be the case.
3. Something went wrong with the machining process, though I can't see how that would affect run-out as only the outer edge of the hub was altered.

Plan B is to use a slightly relieved rear upright with a more modern non-adjustable disk braked Astra rear Stub axle/Bearing/Hub and Disk. This arrangement gives a disk location about 1mm further in and the disk is only 10mm thick. The calipers fit and work fine, BUT the disk thickness at 10mm is around 2.5mm thinner than the Lotus one (adding lightness?) so I'll have to keep an eye on Pad wear.

Modified upright + Astra one-piece hub.jpg

Ideally I'd like to fit Honda rear calipers a la JamieN, which were designed for 10mm thick disks and have a handbrake with a more reliable self-adjusting mechanism. A caliper hanger needs to be designed and fabricated for these, so that's one for the future.

i dont think jamie's calipers will solve the issue with the hub and integrated disk that makes the maintenance costs rather high. ?

although i understand point 2.. i would argue that if we are looking for a alternative that will be long lasting. a non-OEM option would be better as OEM is guaranteed to stop making the hubs where aftermarket units are likely to keep being produced while the vehicle makes it viable in a global scale

[chrism]

Following this thread with interest and still salivating over that silky w/arch pic , but my counsellor/life coach says I'm making progress...

[RonR]

The Honda calipers won't solve the problem with the Daewoo part but will give peace of mind if the Astra rear disks are fitted, as that caliper/pad combination is sized for 10mm disks. If the Lotus calipers (sized for 12.5mm) are used with the Astra 10mm disks there's a small possibility of running out of piston travel before the pads are completely worn, which is why the pads will need to have lots of material left and be inspected more often.

I need to check the rear pad wear indicators vs calipers vs the narrower disks - Measurements to follow...

[Tuga2112]

to which hubs would these astra discs be fitted ?
is there a whole section in the forum about another alternative that im not aware of ?

i know many years ago there was a group buy of rear hubs, but i dont know what else is avaialble or possible. all i know is that id like to avoid replacing the hub plus disk all together next time i have a MOT failure on rear discs being pitted.

[RonR]

The Astra rear disks can be used with the Astra one-piece non-ABS 4-stud stub axle/bearing/hub as used on the Astra G around 1998-2005. The rear upright needs relieving to accept the back of the stub axle, but the bolt holes line up perfectly. The bearing normally comes with studs which are a little too wide and have to be replaced with bolts like the original Lotus ones.
The reason you've not seen a thread about it is - there isn't one yet!

[RonR]

Rebuild finished and MOT passed!
I used the modified upright /Astra Hub/Bearing/Disk setup on the car and it sailed through.
Now on to the next project - but I'll have to start another thread for that!

[chrism]

Phew...I'm pleased for you that you've finally got Silky MoT'd and I thoroughly applaud your high recon standards.
Looking forward to hearing more about that Astra hub mod - and the next project!

[RonR]

Been having a few problems with overboost since the rebuild, at first I thought it was the prototype ECU board I was testing so I removed it and the problem remained.
Tested everything I could think of and nothing jumped out as a cause. Saw a post from Trevor where he was having the same symptoms which turned out to be a Boost Control valve problem.
Long story short - replaced the valve with a new one and no more overboost! Reinstalled the prototype board and it will boost to Everest levels without problems.
Strange thing is, the old valve tested OK electrically and the ported wastegate appeared to work well when boost was fairly low.

[Tuga2112]

Strange thing is, the old valve tested OK electrically and the ported wastegate appeared to work well when boost was fairly low.

just a thought.

i dont know the location of this valve. but if its easy to. it may be worth checking the voltage readings you get in the car at the plug.
ther may be a bad connection or damaged cable allowing lower voltage through and the new valve is more sensitive than the old one, both would operate fine at 12v (or 5) when bench tested, but in real world they may be running at a lower voltage

[RonR]

After rebuilding Trevor's instrument cluster I finally got around to sorting out my own.

Ever since fitting Metal Monkey dial faces I've had a darker area at the top of the Speedo at night, and the blue KPH inner dial was darker than the green MPH outer one. With a trip to Belgium coming up I'll need to see my speed in Km/H, so something needed to be done. LED illumination and an extra internal bulb were the answer.

The cluster's flexi circuit boards were in good condition, but as I'd bought spares a few years ago I replaced them anyway.

My old flexi boards were then used to repair Pinky's spare cluster, which will be winging it's way back to him in the next few days.

The LEDs are much brighter, but there was still a dark area. So - I glued an LED bulb to the top of the cluster, soldered flying leads to one of the other illumination bulbs' terminals and - Voila!

So now I have no excuse when Belgian Plod pulls me over!

[dapinky]

My old flexi boards were then used to repair Pinky's spare cluster, which will be winging it's way back to him in the next few days.

I'm in no great rush for it, so if it suits you to bring it to CC (assuming you are going) then that will do fine.

[Tuga2112]

that cluster looks amazing. Well done!!

[RonR]

I'm in no great rush for it, so if it suits you to bring it to CC (assuming you are going) then that will do fine.

I certainly aim to be there, so will do, Dave.

that cluster looks amazing. Well done!!

It's a pity Metal Monkey stopped making the dial faces, they were really good quality, and being stainless steel the 3 separate dials don't bleed light through the black parts!