Bleeding brakes, sucking air from Master cylinder?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Jason in DLH

Cheeseburger and Fries
Joined
Sep 4, 2020
Posts
1,400
Reaction score
1,562
Location
MN
Yes pedal to the floor. Bad?[emoji51]


Sent from my iPhone using Tapatalk

Yeah...I’ve read that you can blow a seal and/or damage the MC by doing this.

Here’s someone’s take on it..


Not only is it not-uncommon to blow lines while bleeding brakes, it's also fairly common to wreck a master cylinder when you full stroke it if it has nasty fluid in it. Rust can build up in the bore in the normally never used part of the stroke, then when bleeding the brakes you scrape the seal over the rust and now you get a sinking pedal.
 
OP
OP
O

optimusprime

Full Access Member
Joined
Jul 15, 2016
Posts
104
Reaction score
25
So it could be a blown seal within the MC?


Sent from my iPhone using Tapatalk
 

Jason in DLH

Cheeseburger and Fries
Joined
Sep 4, 2020
Posts
1,400
Reaction score
1,562
Location
MN
Hopefully someone else can chime in here, because I’m all out of ideas!

Im really hoping a line didn’t bust!
 
OP
OP
O

optimusprime

Full Access Member
Joined
Jul 15, 2016
Posts
104
Reaction score
25
Well on the plus side, there are zero leaks anywhere so probably not a line


Sent from my iPhone using Tapatalk
 
OP
OP
O

optimusprime

Full Access Member
Joined
Jul 15, 2016
Posts
104
Reaction score
25
Im a total newb at this abs stuff. Is replacing the MC a nightmare job?


Sent from my iPhone using Tapatalk
 

Jason in DLH

Cheeseburger and Fries
Joined
Sep 4, 2020
Posts
1,400
Reaction score
1,562
Location
MN
So it could be a blown seal within the MC?


Sent from my iPhone using Tapatalk


I’m not exactly sure what happens when the seal breaks (never had it happen), so I don’t know what to look for there. Never had a line bust on me either.

Hopefully someone with experience to the aforementioned shows up to the party!
 

Jason in DLH

Cheeseburger and Fries
Joined
Sep 4, 2020
Posts
1,400
Reaction score
1,562
Location
MN
Im a total newb at this abs stuff. Is replacing the MC a nightmare job?


Sent from my iPhone using Tapatalk

Don’t quote me on this for I’ve never change a MC, but I don’t believe it is difficult. Just get rid of all the fluid. Change out the MC. Add fluid and re-bleed. But, this is where you would definitely need a scan tool that can perform an ABS bleed.
 

Forum statistics

Threads
128,781
Posts
1,805,305
Members
91,760
Latest member
MyCleftNut

Latest posts

Top