Hard pedal intermittantly when braking

Levi Palmer · 05-13-2011, 02:30 PM

For some reason I get a "hard" brake pedal from time to time... usually under conditions when I'm driving more aggresively... It never really happens under normal driving conditions. Brake booster was checked for vacuum and was good... I had brakes done thinking that the pads were glazed... but still happens time to time...any ideas? Thanks!

Gcalo · 05-14-2011, 11:51 AM

Your brake fluid has passed its prime.

Fully bleed the brakes, use Pentosin Super Dot 4, and make sure to then bleed the two tits on the master cylinder.

Make sure to suck out existing brake fluid in M/C first, put in new fluid, and then start to bleed. Keep adding to M/C as you bleed each caliper.

mk e · 05-14-2011, 06:05 PM

I would say the vacuum check valve is suspect and I'd probobly just replace it, they're cheap.

KKRace · 05-16-2011, 07:44 PM

I could be driving technique as well since you mentioned it only happens while aggressive driving. If you pump the brake a couple times while on the gas you could use up all the vacuum until you get off the gas for a second. If you are getting happy heal and toeing on the gas pedal while braking you could have a problem.

Very common cause of accidents with old ladys that "two foot". No power brakes when they need them the most.

Remember you only have vacuum when you don't have your foot on the gas.

mk e · 05-17-2011, 08:34 AM

Quote:

Originally Posted by KKRace

I could be driving technique as well since you mentioned it only happens while aggressive driving. If you pump the brake a couple times while on the gas you could use up all the vacuum until you get off the gas for a second. If you are getting happy heal and toeing on the gas pedal while braking you could have a problem.

Very common cause of accidents with old ladys that "two foot". No power brakes when they need them the most.

Remember you only have vacuum when you don't have your foot on the gas.

I knew there was a reason I didn't like power brakes beside the extra weight, they are dangerously unsafe...

Levi Palmer · 06-17-2011, 01:35 PM

So... Ferrari of SF drained all fluid to no avail. Next they changed check valves... still nothing... ordered new brake booster and master.... it's being put in today... I hope it's not the ABS unit... ugh

Levi Palmer · 06-22-2011, 09:24 AM

Booster was bad. Brakes are fantastic again!

Gcalo · 06-22-2011, 09:27 AM

Glad to hear your brakes got a boost!!!

05-13-2011, 02:30 PM	#1
Levi Palmer Owner Join Date: Aug 2008 Location: Lakeport, Ca Ferrari Life Posts: 29	Hard pedal intermittantly when braking For some reason I get a "hard" brake pedal from time to time... usually under conditions when I'm driving more aggresively... It never really happens under normal driving conditions. Brake booster was checked for vacuum and was good... I had brakes done thinking that the pads were glazed... but still happens time to time...any ideas? Thanks!

05-16-2011, 07:44 PM	#4
KKRace Owner Join Date: Nov 2009 Location: Near Olney, MD Ferrari Life Posts: 884 Name: Kevin	I could be driving technique as well since you mentioned it only happens while aggressive driving. If you pump the brake a couple times while on the gas you could use up all the vacuum until you get off the gas for a second. If you are getting happy heal and toeing on the gas pedal while braking you could have a problem. Very common cause of accidents with old ladys that "two foot". No power brakes when they need them the most. Remember you only have vacuum when you don't have your foot on the gas. ------------------------------ Life is Good!

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05-14-2011, 11:51 AM	#2
Gcalo Owner Join Date: Feb 2006 Location: San Ramon, Calif Ferrari Life Posts: 3,613	Your brake fluid has passed its prime. Fully bleed the brakes, use Pentosin Super Dot 4, and make sure to then bleed the two tits on the master cylinder. Make sure to suck out existing brake fluid in M/C first, put in new fluid, and then start to bleed. Keep adding to M/C as you bleed each caliper.

05-14-2011, 06:05 PM	#3
mk e Owner Elite Member Join Date: Jun 2010 Location: PA, USA Ferrari Life Posts: 2,406 Name: Mark	I would say the vacuum check valve is suspect and I'd probobly just replace it, they're cheap.

06-17-2011, 01:35 PM	#6
Levi Palmer Owner Join Date: Aug 2008 Location: Lakeport, Ca Ferrari Life Posts: 29	So... Ferrari of SF drained all fluid to no avail. Next they changed check valves... still nothing... ordered new brake booster and master.... it's being put in today... I hope it's not the ABS unit... ugh

06-22-2011, 09:24 AM	#7
Levi Palmer Owner Join Date: Aug 2008 Location: Lakeport, Ca Ferrari Life Posts: 29	Booster was bad. Brakes are fantastic again!

06-22-2011, 09:27 AM	#8
Gcalo Owner Join Date: Feb 2006 Location: San Ramon, Calif Ferrari Life Posts: 3,613	Glad to hear your brakes got a boost!!!