Renovation of front discs and calipers, replacing pads

I should mention here that most of the front end jobs were actually performed concurrently. Sorting the brakes meant I had to strip the hubs to get the discs off... and that showed  ball joint problem which led to servicing the upper wishbone. At the same time the rack has always needed renovation so that was done too. I've tried to give the jobs some structure with separate entries but this is really s bit artificial! A word of warning- many pad sets don't come with clips or anti-squeal plates so save your bits unless they are obviously unusable.


I started the front strip by removing the wheel... Horrorshow! Why does this car keep kicking me in the balls! It has clearly been a very long time since anyone has ventured in here - cobwebs, dust dirt and rust!

Initial view of front disc/caliper-looks way better in the pic than in reality!

Top ball joint boot split

I had hoped to leave all the suspension items for the time being as they "might" pass the MOT- however the boot was split on the top  balljoint which is an obvious failure so I will have to do this- since I am stripping the hub to get the disc out I guess now is a good time to do this as well...?

Stripping the caliper was the same as at the rear, unscrew the pipe unions, remove the pivot bolt and swing caliper up and push off. The Torque bracket comes off with two bolts behind... but

This was all incredibly difficult- the flexible pipes fitted at the front were a different design and had very slim flats making them almost impossible to grip in a spanner - they were also rusted solid so in the end I was forced to cut the pipes. Dont like doing this as its a bodge but then I'm not refitting these so what the hell.! The caliper then pulled off easily.

Caliper- single large (57mm) piston- not what I had expected. Rubbers all very poor and perished.

Caliper is one rusty lump!

Caliper- stub of pipe still attached. I couldn't unscrew this even when out of the car! 

I cleaned up the threads of the pipe union with a wire brush and left it to soak in penetrating oil overnight. I was able to unscrew it by clamping the metal part of the pipe in the vice and putting a spanner on the locknut.

The Torque bracket was very VERY tight on the wheel- it was a pig to unscrew the bolts despite penetrating oil and there isn't really much room to use a breaker bar. In the end I had to hammer the ring spanners and eventually they shifted and the bracket came off easily once they were out.
The pads were very worn but were fixed well in the bracket and were still sliding nicely. Anti squeal shim dropped out as it was rusty.

Pads very worn, torque bracket very rusty

Whether these were salvageable or not really comes down to whether I can remove the piston without damage. In fact and to my amazement, the piston pumped out easily using the grease gun on my modified nipple (that's not something you hear every day!). The piston wasn't damaged and as these are the  larger 57mm pistons they are more expensive than the smaller ones at the rear- its good to save a little money so I will try refitting the originals with new seals and boots. I may be jumping the gun and taking the other side on faith but I ordered a caliper repair kit w/o pistons from Bigg Red.

In the meantime I started the caliper on the degrease, derust and repaint process I had used for the rears. I  brushed the bracket and caliper in paraffin before spraying that off with carb cleaner and then sonicating at 60 deg for 2 hrs. I then soaked both components in DeoxC overnight before rinsing them well, and treating them with Jenolite and a wire brush.

As usual the DeoxC worked wonders. Jenolite treatment immediately after rinsing (without drying) has prevented flash rust. The calipers were then sprayed in alloy effect UHT paint.

The left side was then stripped

Left side front caliper- even worse!

Pads were very worn- and in this case incorrectly fitted as the spring clips have been left against the edge of the pad instead of under the recess- which causes the clips to stand away from the torque bracket- as in the rear calipers.

Loads of cobwebby detritus needed to be removed.

 Once more I gave up on unscrewing all the pipes and cut the hose in order to dismantle it on the bench.

I pumped out the piston with grease and then started the process of degreasing and de-rusting. The piston on this side did appear slightly scored. The markings aren't really detectable with the fingernail test so may not actually matter, but to be on the safe side I ordered one new piston. Its actually possible that some of this marking was done by the top boot circlip and I would suggest that in all cases the boot and its circlip should be removed before pumping the piston out.

I also needed to treat the discs with de-ruster this meant removing the hubs. I got a bit side tracked with them because of needing to renew oil seals and bearings. I have described the hub strip in another post and the disc clean up is in that one too.

I fitted the Bigg-red kit to the calipers exactly as before, lubricating the seal with brake fluid before inserting the piston.

Caliper renovation kit installed

I ordered new disc pads from Delphi. Their catalogue suggests pack LP17 is right- but they are not! Once out of the box it was clear that they are a completely different size and shape. The pack needed is LP0456 which doesn't seem to be listed on their web site at all? Perhaps its obsolete? I got mine as NOS at a a bargain price on eBay. The pads look pretty much the same as the rears but I can't compare them directly as I've fitted the rear ones already.  Anyway the pack says  for the Lotus Esprit, Excel and Toyota Celica and Supra- which all sounds very promising. Warning though- the Delphi pack doesn't come with clips or anti-squeal shims. There is a school of thought that says that new coatings on the rear of the pads make the anti-squeal shims unnecessary. I would still fit them but (stupidly) I have thrown the old ones away. The clip patterns and distributions are the same as for the rears- pics below.

Anyway- for the inner pad there are clips top and bottom that locate on lugs on the pad. The one nearest the caliper pivot shaft at the top of the torque bracket is the "strong stop" clip. This provides a firm base to take any rotational strain- at the opposite end is the "complex clip"- basically a spring clip with and external spring projecting away from the bracket and disc. The "wavy clip" is  a pad support clip and is installed between the strong stop and complex clips. It has three tabs on one side and two on the othjer. The tree tabbed side faces away from the disc and there is a cutout in the torqure bracket to locate the central tab.

On the opposite side, the outer pad is fixed by two "Vee" clips, their tangs face away from the disc position and their spring clips (the vee part) should rest inside the torque bracket facing down towards the disc when the caliper is on the car. this acts to spring the pad into the recess.  (see rear pad description for an explanation of the terms I'm using here)

overview of clips and pads installed, caliper assembled in torque bracket. Note Vee clip springs are located such that their projecting tangs face awat from the disc (toward the viewer in this pic) and that the Vee clips are located inside the cutouts in the pad springing the pad into the torque bracket. 

 However the pads were a really tight fit. I am reusing the clips here so perhaps a real "Delphi" fitting kit would make everything fit better; however as the pads aren't listed, the appropriate fitting kit isn't mentioned either. The pads did eventually go in and I was able to assemble both calipers to their torque brackets and set them aside until hub renovation is complete.*

I would add that if just changing the pads then these clips can be the work of the Devil. The lugs on the inner pads should be a smooth sliding fit inside the two inner pad top and bottom clips, mine weren't and I needed to bend them to fit more closely around the pad lugs. These two lug clips should also grip the torque bracket so they stay in place while you are trying to fit the pad- if you are reusing the clips like me then they probably wont so bend the bracket clipping tabs so that they do. The inner pad has a lower pad rest/support spring. This also needs to grip the torque bracket and stay there or you will have no chance so bend the small lipped tabs until it grips. Note that the side of the pad support with the three tabs faces inwards (ie towards the same face as the caliper slider spigot and there is a small cut out in the torque bracket to locate the central tab. I managed to get all three clips for the inner plate to stay in place on the bracket but even so I found it virtually impossible to fit the inner pad while the torque bracket was bolted to the hub. I  had to remove the two 19mm bolts to release it and fit the inner pad to it before fitting the torque bracket/inner pad assembly back into place. I could then fit the outer pad which is much easier owing to better access, visibility and simpler mounting clips- and then finally sliding the caliper back onto its sliding spigot- Hold it well up as you re-slide it on or it will knock the inner pad out of place again! You can then swing the caliper back over the pads and refit the swing bolt. NB its always wise to retract the piston using a spreader before swinging the caliper back down EVEN if you haven't changed the pads or disc as I found that the piston tends to move out once the caliper is removed.

Renovated calipers awaiting refit.

Dust shield reinstalled along with the renovated upper suspension arm (see separate entry)

Hubs installed (see separate entry)

Finally calipers reinstalled simply as reverse of disassembly.

Hoses now hooked up so next step is bleeding the system in the hope that there is nothing wrong with my master cylinder and I finally get brakes!