406oc.co.uk

I've just finished changing my front brake pads for an OEM set. The discs have less than 1mm lips and I'm skint after all the recent work on the thing so I didn't get new discs

Anyhow, It took ages to chisel the old pads in, and the new ones needed hammering in I hoped once the brake's been pushed a few times it'd all work itself out, given the old ones were wedged in HARD too

However I just went on a short low-speed kangaroo drive and the pedal's spongy as anything. If I push it fast enough I can tell the front brakes are definitely working, but it's worrying, especially as I need to pass an MOT tomorrow, else I'm borrowing a hell lot of money off someone for a hire car

The hydraulics should be ok - I removed 80ml of brake fluid before doing each side, topped up after changing the pads, pumped the pedal, topped up again

Any ideas what's up? Could it be the lips, small though they are?

Could be the lips - I've known a few sets to have next to no braking force until bedded in.
Some people chamfer the pads to match, idle sods like me rest their left foot on the brake pedal whilst driving Crude, but effective. Obviously don't overdo it & cook something.....
Good luck with the MOT

Tried bleeding the brakes at the calipers?


usually a spongy pedal is caused by air in the brake lines, either caused by heavy breaking heating up the fluid too much, old contaminated fluid, or even there not being enough of it in the little tank above the master cylinder


if it is this, is dead simple to fix

dogslife wrote:Could be the lips - I've known a few sets to have next to no braking force until bedded in.

I think I'm going to have to go for a "rapid bedding-in session" tomorrow lunchtime and put the MOT off until Friday. I seriously doubt it'll pass an MOT as it is now

Phew! Just been out for an "exciting" drive, and the pedal's firmed up... then went spongy... then I took a very easy+slow urban drive... now the pedal's firm again

I REALLY get the whole "huge brake callipers" thing now! With sort of abuse I've just given these pads, I think I'd have reduced the standard 'big 406' ones to treacle! Brake fade happens heck of a lot later, and I'm happy to say the smell is nowhere near as bad That's quite a few vicious 60+mph to 30mph brakings with one or two abs releases while I back off to just under wheel locking pressure

Gave it a 5 mile 30mph urban run afterwards where I didn't use the brakes to let them cool off, got home, and, uh, they're still not that cool Still I don't think they're hot enough to warp the discs. At least I can stop again. That's a good thing

I think it's about time I started taking the coupe out for some more "fun" drives now

Umm, these plates... I'm not sure hammering the pads in is a good thing because they won't release properly. Unless that's between the pistons and the disks that's the problem - it'll ride up with wear. As for the lip, my highly technical solution involves an angle grinder...

Strangely enough, my first job today is to replace the discs and pads on a Hyundai Amica 57 reg, I already had the angle grinder to it to ID the knocking noise coming from the front under braking.

Matt, you must take those pads out again and make them fit properly, even if you have to file the edges of the pads where they fit into the calipers (quite normal, including fitting genuine? pads).The pads should fit in comfortably, not hammered in.

jasper5 wrote: Matt, you must take those pads out again and make them fit properly, even if you have to file the edges of the pads where they fit into the calipers (quite normal, including fitting genuine? pads).The pads should fit in comfortably, not hammered in.

Indeed, 406 calipers are the worst i've seen for rusting up, trouble being they dont rust up and stop sliding like most calipers (not altogether a bad thing). They rust up and the pads stick inside them, i've seen 3 or 4 406's (mine included) that rusted up so badley that one pad was so heavily stuck inside the caliper that it wasn't doing any braking at all, only the caliper against the piston was moving against the disk and as a result was worn down to the metal backing while the other had a good 7mm of pad material left. A god tell tale sign of this happening is if your brakes are grabby, if you very gently and slowley press the brake peddle and get nothing, nothing and then the brakes grab much harder than you'd want/expect, that's a good sign your pads are sticking in your calipers.

Whenever i do the pads on a 406 i always set upon the calliper carrier with a screwdriver, remove all the big lumps of rust around the pad contact areas, then finish it off with a wire brush in a drill. Then clart the contact area with copper grease and fit the pads (also smeared on the back and side faces of the backing plate with copper grease).

Word of advice though, avoid Halfords pads for 2 reasons. Fisrtly i had to sand them down with a belt sander before they'd fit, they were about 4mm each to thick to fit into the caliper. Secodly they fade away to nothing after only a short amount of spirited driving and cause you to miss T junctions, and smell enough afterwards to make old women wait beside your car to tell you there's a bad smell coming from it while you're in the chip shop.

quite a lot of new pads need some "attention" with a rough file where they fit into the caliper slides these days.

Its worth spending an extra 10 minutes a side getting a snug fit, then coppaslip the contact point between the calipers and pads