Brake Pressure Loss, Many Parts Replaced, No FIX...

<thread hijack>
Hydraulic brakes on bikes? I had no idea. Makes sense, but wow. How long has that been going on, and at what price point ?
</thread hijack>

 

pretty common on any decently spec'd bike since at least '05. Shit I run 4 piston hydro on my trail bike. As for price point, at this point cable disc are seriously only on the lowest spec'd stuff or on CX and road bikes. But even that is migrating away from cable pull.

 

Cool. Makes total sense. Haven't touched a bike since about 2000. (Also assume in Florida it might be a little slower to catch on. Not too many hills to come screaming down).
Sorry for the hijack, Please return to your regularly scheduled programming.

 

My brother had hydraulic disc brakes on his bike back in like '96

 

would have been 97-98 at earliest. The hayes mag was still a prototype in '96. I think the first model year production bikes to have them were 98's.

 

you're right! they were normal hydraulic non-disc brakes like the ones below

 

yeah those magura's go back to mid 80's prototypes with 1990-ish as the first production brakes (i think).

 

this phenomenon is inherent in previous vacuum assist Generation trucks not just the new models, many others had this happen to them replaced every part possible and were not able to get the pedal from a deep sinking at stop, only to bleed the brakes till no air is present and adjust the rears to get a livable situation, these vacuum assist models will not have a rock solid pedal at some point there will be a change and no ones really knows why. also on the parking brake there should 7-10 clicks any more than 10 clicks the rear brakes are out of adjustment any less than 7 they are over adjusted FYI

 

Sounds like an experience I had with a Dodge ram once. I did a brake job and swore I couldn't get a pedal. Spent countless hours bleeding, rebleeding, replacing lines, hoses, etc. Finally complained to a friend with the same truck and drove his and the pedal felt the same. I guess I never put that much pressure or realized what happened when I pushed harder than it took to get it to stop.

Was the tech either Joe Dixon or Juan Ramos by chance?

 

let him back in

 

(no problem).. If your planning on starting to diagnose on your own, don't know how handy you are but you can also start to rule out other things like the master cylinder by pulling it out, plugging the holes where the hard lines go and bench bleeding it. once the air is all out you should be able to hold pressure without it fading. if it continues to fade either it still has air or the internal seal is allowing fluid to bypass. I'd help you If we were near. best of luck

 

I'll probably get an ass-whooping for posting in multiple threads, but just getting it out there for awareness as I keep finding threads more and more relevant to what I am experiencing. I have a 2017 SR5 DCSB with 5,100 miles on it. Was driving home yesterday and was startled by how my brake pedal suddenly felt spongy/soft, and could also feel some feedback within the first 1/2" of pressing the pedal (vibrating, shudder, whatever you want to call it). Prior to this, I was actually pretty impressed with how solid the brake pedal felt.

Dealer stated they could not replicate the issue and that everything seems normal. Two separate techs drove it and they inspected front and rear brake components (so they say). I'm not convinced.

 

Possible brake proportioning valve, could be off centered which will make it impossible to bleed the brakes properly.