(GT350) Initial Stop Hard Pedal in cold/wet weather

[Phoenix]

I just changed my fluid to Motul RBF600 and pedal became hard as a rock, stops much better.... Start with fluid flush (20 PSI is plenty) and take it from there.

ive never done a fluid flush on a brake sytem before. i was told 35psi. i have more research to do apparently! is this something that can be done with the car on the ground and the wheels on the car or is it easier with a lift?

is this something that can be covered under factory powertrain warranty?

Sponsored

 

[Austinj427]

ive never done a fluid flush on a brake sytem before. i was told 35psi. i have more research to do apparently! is this something that can be done with the car on the ground and the wheels on the car or is it easier with a lift?

is this something that can be covered under factory powertrain warranty?

Either one works. I'd say a lift makes it a little easier.

And no, brake fluid is a consumable and not part of the power train.

 

[Phoenix]

Either one works. I'd say a lift makes it a little easier.

And no, brake fluid is a consumable and not part of the power train.

yeah im watching autofanatics video on how to bleed the system. easy process once the car is on a lift. he uses a power bleeder. never seen one before. ive always done the pedal method.

 

[TheDeadCow]

Also - quick edit. To the folks laughing at the talk of winter when it's 50* outside, I get it now. After like 100 days above 85* (most of which were at least 95*), this 50* feels legitimately frigid. My internal regulator is completely upside down right now.

Wait until your blood thins out (happens after a few years in desert heat), anything under 70 will feel cold. On the flipside, anything under 100 isn't hot

 

[SVTinAR]

I would take the car to the dealer rather than mess with it yourself. I doubt a change in brake fluid will do anything for those symptoms.

 

[Niz55]

Could be your booster check valve that is going bad .

 

[Hack]

No that doesn't sound normal at all.

I've driven my GT350 in below zero weather and never had a hard pedal. I think you should take it to the dealer. Good luck!

 

[oldbmwfan]

Could be your booster check valve that is going bad .

Agree with this. Sounds like you're losing power assist for the first 1-2 stops and then it's coming back. Test: let the car idle for a while before you drive off (or try to drive further without braking, if safe to do where you live) and see if the pedal comes back faster.

The behavior is definitely not normal and is not safe, though if it's a power assist and not a mechanical problem you should be able to get the same brake performance by really standing on the pedal.

Rust on the rotors, fluid loss, air in lines, and other issues mentioned will NOT create a hard pedal.
- Rust will create some grinding in the pedal with less stopping force than usual per unit of pedal travel
- Fluid loss and/or air in lines will create a SOFT pedal with weak braking force. Will feel "spongy"
- Glazed pads (like if overheated and then rapidly cooled) will create long pedal travel with weak braking force

Hard pedal is either a hydraulic issue (blocked line) or a power assist issue.

Sponsored