1995 DR brake problems

[614justin]

There is no leaks and fluid is at good level
When I hit the brake at night I see my headlights flash for a second and they do this every time I hit the brake pedal.
I barely can stop the boat. I have new pads, rotors and calipers up front and new cylinders in the rear.
This is brake booster or MC? Any help? thanks J

[J Wikoff]

Have the brakes been bled? Does the pedal feel like it sinks to the floor?

[614justin]

Brakes are bleed but have to hold pedal all the way down and takes awhile to stop. No lights on dash or anything. Idk what it could be?

[614justin]

And yes pedal sinks all the way to the floor

[J Wikoff]

That's probably the master cylinder. I don't know how to test it though.

[614justin]

Ok thanks man. When I change it, it's just 2 bolts on the brake booster right? Do I need to bleed anything when I change MC?

[Wes]

You bench bleed the MS before installing. You will then have to bleed everything once the MS is installed.

[MKMike]

I wouldn't jump to replacing the master just yet.
If the brake pedal was OK before you installed the new calipers then you probably just have some more air trapped in the system.
This also happens when the master cylinder gets too low on fluid.
Even a small leak will suck air in every time you apply the brakes, so you've got to be sure there are no leaks whatsoever.

You can bleed your master cylinder and then bleed the brakes at each wheel and see if that fixes the problem before buying a master cylinder.
There's no need to remove the present master cylinder to bleed it.
You do need a helper to hold the brake pedal down while you momentarily loosen the brake line on the master until no more fluid comes out. Then tighten the fitting and repeat the process. You first do the one that's closer to the radiator and after the air is gone from there, bleed the line closer to the firewall.

FWIW, Centric makes reliable, inexpensive brake parts.
A faulty brake booster would give you a hard pedal and trouble stopping.

[96 SSEi]

I would bleed one more time being sure to bleed from farthest wheel to closest to the master cylinder.

also, when you did the pads, did you inspect the sliders?, if the get dirty enough, they stick and can cause sloppy pedal ans uneven wear

[614justin]

I installed new F pafs, rotors and calipers in Feb. & bleed all 4 wheels. I rebleed all 4 last month & adjusted star wheel on E drums and no real difference. Also at night my lights dim for a second every time I tap the brake pedal. I bought the remanufactered M/C today $40 and just reuse old reservoir. I should try to bleed old MC 1st? I never bleed it when I changed front braking.

[96 SSEi]

when you remove the M/C, you have to bleed the whole system at install so I would try the old one first and bleed with engine off and then with it running untill you get hard peddle.

[MKMike]

I didn't realize that this has been an ongoing problem for some time and the brakes had already been bled a few times.
Most likely the master is bad, unless the pedal to the floor only began after the brake work.

Personally, I would return the rebuilt master cylinder and buy a brand new one.
When I worked as a technician, we very rarely installed a rebuilt master because they have a high failure rate.
For much less than $40 shipped, you can get a brand new one from Rockauto .
Centric brand is what I typically use for brake parts.
Just look up the RA posts in the Pontiac Bonneville Club Vendor's forum for the discount code.