Brake pressure question- master, etc

[85montess]

Was reading a post earlier but didnt want to derail OP and take over the thread so I figured I would start a new one. A couple pertinent facts:

- 85 Monte carlo ss
- completely redid the following: shocks/struts, lowering springs, wheels/tires, drop spindles from s10, pads, calipers, drum rebuild, rotors, ss brake lines, hub assembly, etc.
- brakes have been bled a few times and everything is good- no air bubbles

I find that the brake pressure is very weak, especially upon startup. From reading the earlier post, it seems I overlooked upgrading the master/booster. I should note the rest of the brake system, besides what I mentioned earlier, is stock. These are what I grabbed: calipers for both R and L. Could this be my issue? The only other thing I have in mind is buying all new SS brake lines for the front and rear but I would like to save that as a last resort- seems like a huge PIA.

I do apologize if this has been answered 1000 times but its really frustrating me. Warm weather is right around the corner (I hope) and I would love to hit the ground running. The old lady in question pictured below.

 

[Streetbu]

Let's start from the beginning. You brake pressure is very weak. I'm going to guess that you DON'T have a pressure gauge on your brake system. So what do you mean by that statement? Do you mean the brake pedal is low?

 

[85montess]

Let's start from the beginning. You brake pressure is very weak. I'm going to guess that you DON'T have a pressure gauge on your brake system. So what do you mean by that statement? Do you mean the brake pedal is low?

Okay good call. Apologies on the vague description.

When I depress the pedal, there is almost no resistance and it very easily feels like it goes all the way to the floor. Alternatively, when I am driving around and go to stop it almost feels as if I am the one putting the pressure on the calipers as opposed to a hydraulic system. To answer your question, I do not have a pressure gauge on my system, Not sure the best way to describe it, but at least I hope that makes sense.

 

[Streetbu]

Ok that makes more sense. You have a very low (squishy) brake pedal and poor brake performance. You shouldn't need a different master cylinder with those front calipers. Stainless steel lines won't change anything either. You either have a leak or have air in the system, no doubt. A leak should be very obvious, so I'm going to bet you don't have a leak. Next thing is air. I know you said there are no bubbles. Is the bleeder screw on the calipers at the highest point? In other words above where the brake hose attaches?

 

[Streetbu]

The only other thing I can think of is maybe your back brakes are so far out of adjustment because that will also give you a low pedal.

 

[85montess]

Ok that makes more sense. You have a very low (squishy) brake pedal and poor brake performance. You shouldn't need a different master cylinder with those front calipers. Stainless steel lines won't change anything either. You either have a leak or have air in the system, no doubt. A leak should be very obvious, so I'm going to bet you don't have a leak. Next thing is air. I know you said there are no bubbles. Is the bleeder screw on the calipers at the highest point? In other words above where the brake hose attaches?

I am not sure to be honest. I would have to get under there and really look. Sadly the ground is soaking wet and I don't have the time for it now. What would I be looking for if it is or if it isn't? However now that I am thinking about it, I think the bleeder screw is off to an angle on the top of the caliper.

What would adjusting the rear drums entail? Putting them together with all those clips and springs was a pain in the keester.

 

[Dayzedandkonfuzed]

Not sure if this is possible with those calipers or not, but I once chased a low pedal for 3 days on a customers Ford Tempo. She didn't tell me they had just done the front brakes themselves. One pad was crooked in the caliper.... It's still hard to wrap my head around why this would cause a low pedal, but once I corrected that the pedal was perfect.

Air or leaks is more likely, though.

 

[Streetbu]

The rear shoes need to be adjusted out to the point they slightly scrub the drums when turning the drums. It makes getting the drums off a bit of a pain but once you get the hang of it they come right off.

 

[Bitterman]

85montess, I just had a similar issue with my daily driver. You say you just installed front calipers. Is the bleeder screw on the caliper facing up or down? If facing down, you could have the calipers on the wrong sides. I made this mistake and chased weak pedal pressure for a week. Swapped the front calipers around and pedal pressure is back.

 

[64nailhead]

StreetBu ad Bitterman's comments need to be adhered to. If you have either of the issues they are describing, then your pedal will react as your describing.

Answering some questions though might shed some light on your issue though. Did the brakes work correctly prior to installing the S10 setup? If yes, then describe the parts installed on the front i.e. hose, calipers, pads, and were they new or used? Also describe how you bled the system. If no, then let us know so you can head off in a different direction.

To me though, your description sounds like you have air in the system. If the calipers and brakes are installed correctly, then you need to do some bleeding starting with the master cylinder, then onto the rears, and then finishing with the fronts.

Edit : forgot to mention - nice looking Monte !!