front brake very hot, partly siezed piston in caliper or something else?

[chud]

Hi,
Drove about 5 miles home with very minimal braking and got out of car, could smell something hot - front drivers side (OSF) was very hot.

Jacked up car and wheel barely movable, started to take caliper off. In the course of removing bolts gave it a few good knocks with rubber mallet and by the time bolts off I could easily turn the disk in the caliper.

If I press in the two slider bolts they seem to move perfectly freely and spring back easily.

I dont drive it much, only a few thousand a year, but is probably used about twice a week. Appart from the front cross member its pretty rust free. Good nick for 99' car.

Can any of you experts say it definitely points to an issue with the piston or can it be anything else??.. (will give a bit more background in another post below.)

 

[Scott]

Definitely a sticking caliper. Best to either pick up another from a scrapyard or rebuild that one.

 

[chud]

..bit more info....
Last MOT it failed for OSF binding - removed caliper, exercised piston in and out about 5 times and exercised the sliders (seemed free). I also did this on NS and it didn't seem any better or worse than than OSF.
The year before's MOT , same story, OSF binding, although this time I also failed on braking imbalance too, presumably because of this. I 'fixed' this in same way and again both seemed the same.
On both these occasions I never noticed either side getting abnormally hot, or one side hotter than other, before or after doing anything.
It is only now I have a hot one.

Only thing I cant say at this moment in time is how hard piston is to push back as don't have a g-clamp at hand (eep!)

So, is it piston or something else??
Do I take a punt on eBay for a scapper one or a refurb one if so?

Any help gratefully received.

 

[Scott]

If you can get one at a decent price then id say its worth a shot. Theres a few on the bay quite cheap.

 

[chud]

scott, thanks for your reply - do you know if all the ones on a K11 are the same, does engine size or year matter etc?

some of the fleebay descriptions are a bit vague and the pics not great

the p/n looks like 6732170612 (2's may be 7's and vice versa, somewhat corroded!)

 

[frank]

scott, thanks for your reply - do you know if all the ones on a K11 are the same, does engine size or year matter etc?

some of the fleebay descriptions are a bit vague and the pics not great

the p/n looks like 6732170612 (2's may be 7's and vice versa, somewhat corroded!)

i think march,s have a smaller vented disc chud, and some 1.4,s are vented but stock dia :grinning:

 

[chud]

if anyone is interested I swapped the caliper with one from a scrapper and it seems ok now. just writing this for info if anyone searches the board for same issue...

only needed about 1/3 of a 500ml bottle of DOT4 to bleed it through. (i bout 1l and this may save someone buying too much!) - dont bother buying any kits, u just need abit of flexi see-through rubber tube and and an assistant with at least one foot to pump the brakes, alot easier than i thought.

its also almost fixed another issue i had that the car sort of chugged when almost off throttle, i guess the binding brake was causing that or contributing to it, however it had been like that for over a year or so and had assumed it was just a 'feature' of the car. Until this obvious overheating the breaks always seemed ok though, i guess it can bind to an extent before it starts really heating the brake up and you may not notice, but it causes chugging when just on throttle slightly. wierd.

 

[r-reg-sr]

might have to clean idle valve?

 

[dg_unit]

I had the same happen to my Impreza after throwing it around in the snow last winter. If you're daft enough to leave it be as I was it starts to look like a ceramic disc with a bit bright glow.

 

[smiffy]

I had the same problem with one of the stock cars, the two sliders had seized up took them out cleaned them up with sand paper, worked fine for a while then seized up, I was told that if you grease them up with a special grease - not regular grease as it could be a fire hazard it should fix the problem altogether. Can say as havnt done it yet