Road Hydraulic Disc brake query ...
 

Has anyone here experienced anything like this with hydraulic disc brakes ?

I have a road bike with Ultegra hydraulic disc brakes.
I'd say the bike has about 2000 kilometers on it, not much.

A couple of weeks ago at the start of ride, the braking force was dramatically diminished. The pads had been exposed to some kind of oil, either a leak from the calipers or something sprayed up from the road. The weird bit is that it affected both brakes, front and back.
Anyway, while I should have turned for home right from the start, I rather persisted with the ride and after a couple of hours (about 50 km.), enough of the goop had been scraped off the pads that I had reasonable braking again.

Satisfied with that, and lazy enough to not do a detailed investigation, I left the bike alone until the next ride a few days later.

Next ride the pattern repeated: the ride starts with **** braking which improves over the course of a couple of hours until by the end of 50 km or so, reasonable braking is restored.

I've finally gotten around to my question - thanks for reading this far...

Trying to determine the cause, I can think of two possibilities. Which do you figure it is ?

1. I've got hydraulic system leaks both front and back. After every ride, the leaks saturate the pads again - and **** braking performance is the result.

or

2. The original contamination of the pads persists. Despite having cleaned rotors and pad surfaces between rides, oil now embedded in the pad substrate rises to the surface again between rides and the solution is to replace the pads.

I think that 1. is more likely the explanation, but why leaks would develop in both systems at the same time baffles me. ( Shortly before this all happened, I did a road side flat repair which had the bike upside down for 15 minutes. That wouldn't cause system leaks, right ? )
As for 2., how much mineral oil can a brake pad absorb ?

Thanks for you time.
-jg-

If Scenario 1 is true, I'd expect you to notice longer lever travel before your brakes start to bite. It would be a weird coincidence for this to happen to both at once, and I don't think inverting the bike should cause it.

From what I understand, it doesn't take much contamination to wreck disc pads.

Well, if you have a leak in both systems you should be getting low in both reservoirs. Is this happening? If not, I would go with (2), and replace the pads after cleaning the discs with a solvent such as Brakleen and examining the calipers, etc. for any fluid deposits. Once pads are contaminated it is very difficult if not impossible to decontaminate them.

Thanks to adamrice and dsbrantjr for your well considered feedback.

I'll try some of your suggestions - new pads for a start.
I'll post here with an update.

-jg-

Pull the old pads out and have a look. Don't throw new pads w/o doing that or you could just be wasting money. If there is obvious contamination (which is likely) you need to fix that before you kill another couple sets of pads.

Right, I'll look everything over before making changes.
"Signs of contamination" is the first thing I'll need to learn about.

Also, with the state of the parts market these days, finding new L03A pads would be a miracle. Its the same with the Swissstop alternative (Disc 34 EXOTherm2] - no one has them in stock.

-jg-

I've cleaned pads that were generally new and that I suspected were contaminated (made a hell of a racket at low speed). Spray brake cleaner on them, then burn it off (using a long stem grill starter to light it). Obviously: do it outside, and use a pliers to hold the pad, because it will get hot. This has only worked if the contamination is light, when I broke a piston and saturated the pads, there was no hope. But, contaminants from the road or fingers seems to respond well to this. If you choose to do this, make sure you test the brakes before you set off to bomb down your local canyon descent.

I am comfortable doing this, and have had good results.

Thanks also to Badger6 fo the cleaning tips.

-jg-

Fixed.
 

A followup to the post...
The solution to this problem was really just a good cleaning. The steps were:
- thoroughly clean rotors and pads with acetone
- sand down the surface of the existing pads with 320 grit sand paper
- generally clean up in and around the calipers
The result is restored braking and for the most part, silence when braking.

For me, the bottom line is learning that apparently contaminated pads can be salvaged in some cases.

Thanks for everyones help.

-jg-

Thanks for letting the hive mind know the outcome.

Yeah, cleaning contaminated pads is a bit of a chore but it's doable. I usually just avoid the hassle and toss the pads if they get oil on them. Could be a good idea to carry a spare set or two on the road.