Wacky Brake Wear

[Reedy]

I was too curious so I pulled it all apart, dropped the wonky brake pads in and recorded what happens when I pump the brake pedal. The whole caliper flexes sideways. Actually in the opposite direction to what I thought, it flexes in at the bottom, not the top. This movement is definitely in the guide pins.

Brake Caliper Flex - YouTube

[RedDjinn]

the caliper looks bent down, damn your putting some force through them! If your gana track you need stronger brakes and brackets!!!

[Reedy]

Video with evenly worn (almost new) brake pads in it.

Brake Caliper Flex 2 - YouTube

[juld0zer]

Hey mate,
i've kept pretty quiet about this one. been paid out for my brake 'upgrade' on my diesel and the numerous issues ive had.
Grab a set of these: TyrolSport Brake Caliper Stiffening kit

The Golf R/R32 uses the same caliper design (slight differences but it is pretty much the same ATE unit). The bushings fit perfectly and resolved all my ticking noise issues - the stock rubber bushings aren't good enough and caused the caliper to shift under braking and even when i turned the wheel, that was enough force to 'drag' the caliper in a different direction.

There's a few articles to read about these bronze bushings, both from Tyrol themselves and independent end users. Ignore the comments about seizing etc due to road salt corrosion as it's irrelevant here.
I've had them installed for about 1000km so far. Pedal is firm, there is a lot more control/modulation over brake force. Although the stock on/off feel is awesome for commuting and panic stops but you get used to it.
Most of the VW guys report shorter pedal travel but mine actually increased. Then again, my car is not a real MPS and therefore has a different booster and master cyl.

Let me know if you want more info about the install etc but it's fairly straightforward unless you've got larger fingers. It took me about 2 hours all up but i removed the calipers from the car and did the work inside the house (too cold at night). Although installation in-situ is possible (and quicker as you dont have to bleed, I highly recommend removing the calipers as it's quite a fiddly job and you dont want to drop the caliper on your foot/shin or stress the fluid line. (cover the line port with a big rag when you remove/refit the pads to avoid spraying fluid everywhere).

[juld0zer]

BTW might be a good idea to inspect the pistons for uneven wear as sloping pads can't be doing them too much good..
and about the retaining clip, i believe it's also there to help retract the caliper when you take your foot off the brake pedal. Although it was hard for me to prove this to myself, on the regular Mazda3 calipers that is easy to demonstrate. But their clip is more like a coat hanger spring.

I replaced my retaining springs too just for good measure. Equivalent genuine Saab parts are a about 25% of the cost of the genuine Mazda/Ford/Volvo part but i personally dont think it's going to do much for your sloping pad wear problem.

[Reedy]

Very interesting! And here I am shopping around for a big brake kit.

Were they bushings easy to remove and replace? I will definitely look further into this, great find mate!

[juld0zer]

The stock rubber ones are easy to remove - use a flat screwdriver and lever the lip towards the hole (from the inside of the caliper) while pulling on the dust boot end with sturdy pliers. Might help to use the pliers to rotate the bushings around a bit to break up any goop.
The bronze bushings come with keyring style stainless 'clips' which is where small fingers and stiff finger nails come handy. The original design had circlips which were easy to attach but there were a few failures reported and some of the folks in the US/Canada experienced corrosion of the circlip, resulting in failure.
The kit comes with replacement stainless steel caliper guide pins which must be lubed up with Stalube brake caliper grease prior to installation. You have to remove and regrease the pins every 10000km or however often you like but if you change pads often then it's not going to add much time to the job My kit came with a sachet of anti-seize. The first kits came with Stalube sachets, i'm not sure why they changed to anti-seize but i'm using Stalube.

The hardest part is doing the clip rings but once you've done two, you'll get the hang of it. Essentially you hook one end onto the slot and run your fingernail along so as to guide the ring around the slot. Once you've gone thru one revolution, there is a ridge which ensures it wont spring off so the remaining part of the ring is easy to complete. Sorry i'm not great at explaining but this pic will give you an idea of why it's a pain. The pic looks like a c*ck hahahah

There's an install guide on some of the reviewer's posts. Just dont pull them like a slinky!

[Reedy]

Sweet. The MPS caliper is slightly different but it probably uses the same bushings.

Will look further into this, might see if I can get confirmation that they will fit. The thing is that the rubber bushings are designed with a little bit of give in them for a reason, so a solid metal arrangement is going to have some drawbacks. If they jammed then I could see some rather bad failures. Or possibly having a caliper break rather than the bushing simply giving way......

[juld0zer]

Yeah it's very slightly different - the back has some sort of balancing weight and the flexi line does not connect directly to the caliper but rather via a short angled hard line and the flexi line is installed upside down. There's 2 styles of retaining clip, the type used on the MPS is also used by Saab but according to Saab, the 2nd type has superseeded the MPS type therefore making it identical to the Golf R/R32 clip.

The bushings are identical in both cars, and identical (oddly enough) to the SP23/25 caliper because i swapped out the bushings from my factory Diesel brakes (same as SP23/25) thinking that at 6k old, there's nothing wrong with them. ATE part numbers stamped on the bushings themselves matched up. A lot of VAG, Opel, Saab, Ford, Mazda, Toyota, Mini and a few others use the same bushings - but very few of these makes have calipers that weigh as much as our calipers.
They will fit, i took the punt as a last ditch resort (next was going back to blank rotors). I drive my car daily but not to the level that you do (my gf would probably leave me if i tracked my car haha).

I do agree that the bushings are rubber for a reason, but i've experienced no perceivable odd noises. There might be a tiny clunk over coarse surfaces/potholes but IMO it's nothing. i pulled them out at about 800km and there was almost no wear evident on the pins. I do fear them jamming but i think i'd notice it before anything significant occurred. I'm in the process of trying to invent a cap to seal off the exposed end.

If the pins did snap, the inside of your wheel would catch it and there would still be sufficient pad contact to halt the car. I might just change the pins every year or two, with OEM pins if i CBB to get the Tyrol stainless ones. FWIW, my stock pins were pitted at 6000km. I can't see why because the dust caps were present aswell.

Either way, i'm happy with my punt if you're in Sydney you can come have a go and inspect it.