brake pedal hits the floor.

Bludge · Post by **Bludge** » Sat Apr 19, 2014 10:21 pm

i have just replaced my brake lines with braided hoses, put drilled and grooved discs and new pads on. i have bled the brakes and aside from miniscule air bubbles in the passenger front that i cant get rid of, all the lines are air free and the brake fluid is new.
there are no leaks i can find and the pedal doesnt lose any pressure if kept half down. it pumps up firm and dips when you start the engine.

i just took it out to try some emergency stops and the brakes are the best they jave been since i have owned the car, and a real slam down at about 35ish locked the wheels into a skid (no abs).

do i have a problem? im thinking the pressure in the system should prevent the pedal touching the floor but the lockup would indicate max pressure to stop the wheels comes before that happens. not sure what to make of it.

Post by **Gayno** » Sat Apr 19, 2014 10:23 pm

Pedal shouldn't touch the floor. Don't underestimate how much those "miniscule air bubbles" can compress.

Ideally you need to bleed and bleed until everything is out.

Post by **Thebusofwoe** » Sat Apr 19, 2014 10:26 pm

Either that or during the bleeding process your master cylinder has gone up the shitter. Have seen that before, and even done it myself

Post by **4th Gen Doug** » Sat Apr 19, 2014 11:16 pm

^^ This..
Deffo need to get the air out of those lines tho - a pound to a bucket of bum droppings that's where your problem is..

Bludge · Post by **Bludge** » Sat Apr 19, 2014 11:36 pm

Thing with the air bubbles in that line though is i was bleeding for ages, way more fluid passed through then i would imagine is in the line. maybe air is being drawn in somewhere?

do you mean the seals in the master? as there is no loss of pressure when the pedal is depressed and held like when the seals in the old one had gone.

the only other thing i can think of is that when i changed the master i was missing the rod seal ring so i added one, and it was suggested the old one might have been retained in the servo, so i may have ended up with 2. could this be causing it? worth taking the master cylinder apart?

Post by **4th Gen Doug** » Sat Apr 19, 2014 11:49 pm

Mate - I missed you saying you changed the M/C as well..
Did you prime it before fitting? if you didn't, it's probably borked (the seals anyways) - I did this myself..
Also worth checking the vacuum line to the booster while you're there..

Post by **Thebusofwoe** » Sat Apr 19, 2014 11:51 pm

Tbh it sounds like air in the system. There is a way you can almost guarantee this, drive along at say 15 or so mph. Hit the brake pedal, release and hit it again. But do it quick. If the second time you hit the pedal it feels further up and harder then there is air in there somewhere

The type of rear caliper that the ludes are fitted with are very good at catching air in the parking brake mechanism and not bleeding it out.

Bludge · Post by **Bludge** » Sat Apr 19, 2014 11:55 pm

by prime do you mean bench bleed? I didnt as it came second hand so i didnt think it was necessary?

TBOW thats how it feels if im stationary and pump the pedal a bit, the engagement point comes right up. havent tried it moving like you said though. sound like air in the system?

all the fluid was bubble free apart from that one caliper, should i just re-bleed that caliper until the bubbles stop or do the whole lot again?

Post by **4th Gen Doug** » Sat Apr 19, 2014 11:56 pm

Tbh it sounds like air in the system. There is a way you can almost guarantee this, drive along at say 15 or so mph. Hit the brake pedal, release and hit it again. But do it quick. If the second time you hit the pedal it feels further up and harder then there is air in there somewhere The type of rear caliper that the ludes are fitted with are very good at catching air in the parking brake mechanism and not bleeding it out.

^^ Yup - makes sense, try this before taking your M/C apart for sure.
Nice one @Thebusofwoe

Post by **Thebusofwoe** » Sun Apr 20, 2014 12:03 am

If i was you, i would bleed each front out 15 pumps. I know its a faf but the best way to ensure that the air comes out the rear caliper is to unbolt them, unbolt the parking brake cable, and remove the caliper but keep the pipe connected. If you can, g clamp the piston so it doesn't push out, then bleed the caliper whilst rocking it around making sure the bleed nipple is always at the top. Its a massive faf but sometimes, the only way to get the air out of the back of the caliper.