bigshot

Hi folks !

So I got my rear brakes pads and discs changed not long ago and I'm noticing a lost of pressure on my brake pedal.

At times it feels like it goes all the way in and it's scary.

What would be the main cause of that ?

Pointers will be appreciated.

Thanks in advance

homer

When you hold your pedal down, does it hit a tight spot then slowly go to the floor? That would more likely indicate a leak.


What you're stating though sounds like there's excessive travel on one of the pads (or more). It could be a pad/caliper not installed properly. If the piston is too far away and it's having to move a significant distance in to engage the pad each time you press the brakes, it could cause that same type of issue. It's pretty hard to install the pads wrong though from what I recall lol. I did just help a friend with a similar issue on an ATV though. We could max the brake out but it was the pad was installed offset by mistake.

Then again, it could also be your master cylinder going... What's your fluid level look like (although you'd have a warning and bigger issues if it was low)?

bigshot

It doesn't look like anything is leaking and brake fluid level is still proper. When I press the pedal, sometimes it feels normal and other times I feel a tight spot then it slowly goes to the floor almost like I'm losing braking power.

Texasreb

That sounds like an internal leak in the master cylinder to me.

bigshot

Internal leak eh ? So gonna have to replace the master ... Was fine b4 the disc and pad change.

homer

That's why I say. Better to check pad installation first. Ivr seem the master cylinder leak before too however with brake pads if there is excessive travel on the caliper its going to multiply in your brake pedal. Not saying it cant be master cylinder but I'd check that first as its fairly easy.

Especial86

iTrader: (1)

Start with a full 4 corner bleed. Check the condition of the old fluid as well.. If its got a lot of green color in it then its got some water contamination.. Brake fluid attracts water.. Exposing brake fluid to open air, especially on humid days can ruin good fluid..


Other culprits could be a brake line that's worn and expanding too much, or a leaking master.. If you have any rust under your master on the brake booster body, then this "could" be the sign of a master leaking..

If its still soft after a bleed, pop a wheel off and inspect the pad to rotor surface.. Its possible the pads are glazed and were never broken in and seated appropriately. Any corrosion on the caliper bracket slide rails (what the pad ears rest on), or a caliper bolt with no grease can cause a "hang up" too..

Mechanik

It is "soft" at specific times, like right after start? Or is it random?

bigshot

Id say more random.

JimmyB1232

Sometimes shops/mechanics will compress the calipers without removing the cap on the master cylinder or loosening a bleeder valve which just puts air in the system and if your fluid is old and dirty it tends to bubble up more causing more of an inconsistent feel in the pedal. If I were you I'd bleed all 4 calipers and see if that helps at all.

If that doesn't help, you might want to inspect the calipers and make sure the seals aren't blown and the pins/guides are nice and clean and lubed up.