Right so this is a while coming.
The handbrake on all Bmw's I've ever driven is rubbish.
Any car I've seen just scrapes past the nct also. As in really just about with a lot of adjusting pre test, and backing off again after.
I never use the handbrake since its an auto, but every single year its failed nct on the handbrake. New shoes, discs, cables(a pain to change) etc...still no good - in the end I used to go down with them so_tight ya wouldn't be able to turn wheel when in the air with the wheel off the ground. The drill has been for the last 6-7 odd years was Go down, scrape pass it....then back them off again for the year.
This was madness and had to stop as I've made up my mind to keep car another few years as I don't care for anything else out there to be honest.
Traveling back to Ireland the last day I had a few hours flight time to think about it. I knew spot calipers existed for F3 and Rally cars, but what they looked like I had no clue. So I started looking. I didn't want to go the combined hydro+Mech caliper from Wilwood. Reasons were, they are 4 piston, and different pad area, which would screw up the bias front and rear.
So I looked into spot calipers and found the ones below. I figured they were worth the punt and had to be possible to cobble on there somehow. I entered the project this eve blind half thinking I would have to get bespoke cables made for them to work. I didn't mind that too much and the car could be back on the road in the morn without working cables/handbrake - but the main calipers working. Picked up a bit of 6mm plate, and 10mm plate for whatever the bracket might look like. Having no real idea what it looked like back there I figured there was room to mount the new caliper at the top and bring some form of bracket up around from the original caliper carrier mount bolts.
The new calipers were about 200euro delivered from the Uk.
The new discs and pads were 180 or something near that. The Discs are OEM - these yokes are heavy on brakes and I find aftermarket discs warp in a heart beat. In 6 odd years Ive gone through about 10 pairs of front discs, and probably 15 sets of pads.
So here are the spot calipers - I could have made these I guess, but time is tight this weather,
This is where they are to go...someplace...
There is also a steel bracket with them that's not shown below - pic of that later,
Removing all the junk,
This is where the project took a major turn for the good...the shoe locator stop which I didn't know was there is held on with two bolts...pulled it off and its a meaty bracket indeed so hoping to put the new bracket off that somehow. Offsets were still a major concern,
Removed the backplate also to make room.....just my luck it wouldn't fit over hub - there wasn't a hope in hell of removing the hubs again as they nearly crippled me removing them both a while back to do the bearings(the half shaft splines seize in hub)so out came the grinder,
Its going to have to get chopped anyway,
The handbrake Mech at rear can be clocked 60degrees at a time by removing the three bolts and rotating - I chose to leave it at that position for the mo, as it looked like it might work that way,
A bit of CAM - no major science here...the bottom holes are the hub where the shoe stop came off - the top holes the new caliper holes. In terms of distances from center, left approx 3mm clearance at edge of disc to caliper.
I was taking the bracket from 6mm plate, and at this time still ignoring offsets. I figured it could only be one of two ways when mounted...caliper too far in, or too far out...machining, or a spacer would fix that either way so I plowed on with machining the basic bracket first.
Profiled them out on the cnc - 6mm thick mild steel plate, 6mm solid carbide cutter at full depth - 6000rpm and about 150mm per min travel speed, full flood coolant,
Missed a photo here, but offered them up, and low and behold the offset was bang on with the 6mm plate!! So out with the tig and welded them onto the Wilwood plates. A side note here - if anyone is using these calipers on anything - fire away the Wilwood plate and use your own plate right onto the caliper to save the weight of the two bolts which are needed to bolt the caliper onto your own plate. The Wilwood plate is tapped 3/8-14 tpi also....more the reason to fire in the bin!
Here is my own plate(6mm), welded onto the Wilwood plate(10mm)
Heated them up to 'very hot' and gave them etch primer....
Then gloss black, you can see the full shape here below of the Wilwood plate and also the outermost 3/8" mounting holes - which I'm not using.
A bad shot of the newly chopped backplate,
Still no real idea if this will work....hmmmmmmm,.,,,
Bracket on as well as newly painted chopped backplate - I suppose I should have ordered new backplates but to be honest lets just get it functioning first....backplates are dear enough - nothing but genuine goes on this bus. From memory they're nearly 260euro for the pair.
Bracket just showing above disc and looking fairly ok,
New disc on and by jingles she fits...
At this point I thought the cables were for the bin and wouldn't work as the cable bit was very short. Went into the car to undo and noticed there was a fair bit of them in the car that had been tensioned up last year. So....I slackened off and pulled them back maybe 10mm.
Got under car and reset the sheath/cable hangers a bit and what do ya know...they worked perfect!
Granted....they don't have the correct end, but they are on there very secure and not going anyplace. An m8 bolt across the hole for different end makes sure the clevis cannot widen, nor can the cable jump out. Very very lucky indeed.
So there you have it......have an EPIC handbrake now and well chuffed it was as easy as it was. Its all legit I feel and pretty factory looking from inside and out. The glint of the 2nd caliper behind the rim also makes for a talking point!
Lets see what the nct boys make of it in a week or so,
Once Ive the rest of the stuff in that is that I don't think it needs but its good to freshen her up all the same as it does a LOT of miles.
Pretty sure its the only E39 in the world with dual rear calipers. Not sure that's a good or a bad thing...but it works for me!
Over and out,