question about brake pedal. to the floor on first pump stiffer with each pump

[kooter]

hello and first off this is a 1990 galant base model fwd 2.0 sohc 5spd 195,000 miles. My daily driver.
So recently I have been noticing that when I go to hit the brake pedal it goes almost to the floor before braking begins. If I let up and press it again it feel much stiffer and braking happens sooner. and if I press it again much much stiffer braking happens almost immediately.

So I just lookied around a little don't see anything leaking in the engine bay. Booster, master, proportion valve, any lines.
I am only guessing that my brake booster is starting to fail but wouldn't that cause a harder pedal not softer.

also when the pedal has been pumped a comple of times it stay stiff until release it doesn't fade or sink to the floor. Although if you press harder it does go down farther.

Just curious if I should prepare for a total brake failure, i.e. drive fast and take chances.


any advice would be appreciated. will be looking into this more next week. with any luck the gvr4 and 90 base have the same booster if that is the problem as I have two from gvr4's.


thanks as always

 

[GSTwithPSI]

Was the fluid level low? What you are describing sounds like air in the lines. Air only gets in as the result of a leak. Does the 90 have drum brakes in the rear?

 

[transparentdsm]

or if the hose from the intake manifold to the brake booster is leaking.

 

[FlyingEagle]

100% sure all the pads are seated properly?

Been a while since I looked at rear pads for those calipers, but if they have a pin that needs to line up with the piston,
it will have to be seated in the groove of the piston so as to not be cocked as it compresses.

If that is not the case for these rear pistons, then you could have a seized or seizing slider pins.

Seized/seizing slider pins make the pistons extended just that much further as the caliper cocks during compression.

This equates to extended pedal travel.

Also, make sure you don't have rotten shims/rust between the pad backs and calipers/pistons.

Any of these irregularities will cause improper pedal travel and or feel to varying degrees.

 

[kooter]

Fluid level was fine. I started the car and sprayed brake cleaner around the booster and master. Nothing changed didn't notice any leaks. Rear drums . Problem is fairly recent.

 

[kooter]

Pads and shoes have been on the car so long I can't remember when they were last replaced. Pretty sure the fronts were done a year or two ago.
I bought this thing with 113 thousand for 419 dollars tax title liscence and dock fees. As much as I hate to admit it hasn't seen much in the way of maintanace. Shock struts twice. 3 altermators couple batteries. Exhaust minus a muffler . Pretty sure I did a tune up 4 or 5 years ago. It is st this point kinda a point not too just to prove how well this car was made.
Prepare your torches and flame throwers. I have not yet changed the t belt or the water pump. Still starts right up and runs great (except when it rains. Coil pack is cracked so moisture causes arching.) Long story there.
Anyway I am getting off track. It is gonna get some much needed love very soon. Really I promise. It just has never asked for much.

 

[GSTwithPSI]

Ah, rear drums. I would be willing to bet one of the wheel cylinders in the back is leaking. It is common for them to leak, and not be able to see it visually until you pull the drums off. Pull the rear drums, and peel back the rubber boots on each wheel cylinder. Look for the boot that is wet, as that will be the leaky piston. Take a close look at the back plate for each drum, and you may be able to see signs of leaking there as well.

 

[EgonOlsen]

Or the seal inside the brakebooster leaks, which make the oil go on the other side of the piston. Fairly common on them, just swap out the booster.