Well I’ve just installed my Brembos so I thought I’d add a description of what and how to do it. I went for the adapter plate.
What you’ll need is:
8 off 3/8” UNF high tensile countersink bolts 1” long
8 off 3/8” UNF high tensile countersink bolts 1 1/4” long
2 off M12 washers. They should be 2.5mm thick.
Pair of vented discs from a Peugeot 406 or Citroen Xantia. They are 283 diameter. The later model 406 had 305mm diameter discs which you don’t want. They will need machining down to 280mm diameter. Don’t go bigger 280mm is very close.
A pair of Calipers from a Peugeot 406 3.0 coupe. They are getting rarer and expect to pay £150 or more. I got mine a few years ago for £60.
A pair of brake hoses with a 10mm banjo fitting one end. If you have new brake hoses you might find you can unscrew the fitting on the Caliper end and just change that. I bought mine from Black Diamond which is UK company I’ve had great experiences with. I think they may have this on their website now.
Brake Pads. Mine are Black Diamond Predetor PP149
The adapter plate. You’ll see below that the one I had made used the wrong dimension for the PCD for the disc to plate bolts. I got the dimensions from a previous post and wished I’d measured it myself.
First remove the Caliper and hub. Place a rag under the hub just in case the rear bearing falls out. Then remove the disc splash cover. All but one of the bolts snapped when I undid them. Don’t worry you won’t be fitting it back on.
Then remove 4 bolts holding the disc to the hub.
Next is getting the adapter to fit the hub. Now I would advise you measure your hub. I’m not sure if they are all slightly different but I would have made the hole in the middle 66.6 diameter. I spent more time than I’d liked to open it up and filing the hub to slide on the hub.
Now one thing I don’t like about this design is using counersink bolts but it’s not avoidable unless low head bolts and machining the disc to allow the head to sit in it. Two problems, first, counter sink bolts could come loose as no locking washer can be used. Loctite can be used. The second is the alignment of all the holes. You will probably find either the adapter or the hub will have slightly out of position centres. Unfortunately with countersink bolts alignment is critical as there’s no play or clearance. I had to move the adapter around on the hub to find one position that lined up all the holes. You’ll see my plate started of with 6mm holes that I opened up , tapped and countersink myself. I would suggest you get the plate made complete to the drawing above.
If you countersink the holes yourself you’ll need an 82 degree 20mm dia countersink bit. Make sure the bit is lined up with the hole and then clamp the disc down or you’ll end up with a pentagon shape. Go really slow on the speed.
The bolt heads are about 6.5mm deep so go about 7mm deep to ensure the head surface is below the surface of the adapter. I ran a tap down the hub threads to get rid of the rust at the end of the thread. This helps tightening the bolts later. Use the 1 1/4” long bolts.
It’s good to shampfer the inside edge of the adapter plate central hole. This ensures the faces meet up nicely but the hub is machined right into the corner.
So your adapter fits the hub, next is fitting the adapter to the disc. Getting the adapter perfectly in the middle of the disc is important or the disc will have a run out problem or wobble. This is where you will hopefully be doing it differently to me as your PCD should be 108mm. This way the holes will line up with existing countersink holes in the disc. However I marked up where I needed the holes then using folded paper tightly packed in four positions I got the adapter to sit tightly in the middle of the disc.
Drill one hole and place a drill in it to ensure al the other holes line up when drilling them. Then countersink the back of the disc to take the 1” bolts. You don’t need to go the whole 7mm deep. Unfortunately the original bolts won’t go back in as the heads will now foul the stub axle as the disc is that much thicker. This may differ to what you do. I started with 6mm pilot holes and opened them up 8.5 on the adapter then tapped out to 3/8”unf and put a 9.5 hole in the disc. If your adapter already has tapped holes then spot through with a drill to mark the position of the holes. Again I advise you have the adapter made finished unless you have access to a mill or at least a pillar drill. You will need to keep the holes and threads straight because of the nature of countersink bolts.
Get used to marking the parts up this also goes for which hub goes on which side of the car. This ensures the holes line up and the hub bearings go back where they came from. If you don’t the bearings may fail and you’ll for ever messing around trying to figure out what holes line up.
Now fit the adapter to the hub using a 5.5mm Allen key and a bar/tube to get some decent leverage. The bolts should be torqued down tight. The Manual says 90nm which is tight so don’t use an old rounded/worn key.
Now fit the disc to the adapter plate. Tighten bolts as before.
Before fitting the hub back on the steering arm will need to be moved to allow the Caliper to fit. The bolt hole flange on the brembo is 20mm thick which is 2.5mm thicker than the original. Remove the second bolt holding the steering arm on and put the M12 washer between the arm and the stub axle. The steering toe in will need to be adjusted and I’ve found turning the rod ends in one turn on one side and two turns on the other gets the tracking back to where it was.
I found someone had put the wrong bolts in and one only had threads holding the steering arm on. I probably went a little overboard and cut down some long shank bolts so the shank went into the Caliper. The Caliper bolt holes are a little bigger than the original so I wanted to take up some of the play. Stick a little copper grease on the threads.
Next fit the brake hose to bulkhead and Caliper. I took the opportunity to regrease the hub. Then fit the hub, tighten nut to book and back off 1-1.5 turns and fit split pin. Fit your new brake pads. There’s different opinions with pads but I’ve gone for black diamond predators. They’ve got pretty good reviews, are fast road rated with fast bedin layer and are a third the price of other recommended pads.
When they’re in tighten up the Caliper and steering arm bolts and bleed the brakes. Left side first then right then rear if t like me you decide to change the rear hose.