[RedPepper]

Hi everyone, quick question for all of you.

Recently I noticed that my brake pedal seems to be spongy and travel further than normal when braking. The pedal use to travel an inch or so and firm up with constant pressure to slow the truck. As of now, the pedal goes down about 2 ½” or so before becoming firm enough to slow the truck. Not very confident braking, almost like stepping on a firm marshmallow.

The temperature has dropped recently and has been in the low 40’s in the morning while driving to work. Not sure if this would cause the issue or not.

A few tests that I have completed-

With the engine off I pumped the brake pedal to obtain pressure in the system to test the master cylinder for an internal seal leakage. The pedal stayed firm and did not sink down while my foot held pressure on it. The master cylinder seems to be fine after concluding this test.

The brake booster connections are all tight and the hose does not show any signs of cracking or leakage. The brake pedal is easy to push down and does not require an unreasonable amount of pedal pressure to stop the truck. The brake booster seems to be fine and in working order based on this observation.

I checked the master cylinder reservoir and the fluid seems to have dropped a 1/16” or so. I checked the brake calipers and rubber brake hoses going to each wheels for any signs of leakage. None was found.

The only thing that I can think of is that I have air in the brake system since the pedal is spongy and travels further than normal. Another thing is I just installed new tires and rims onto the truck a few days ago and started noticing this issue right after. Could new tires cause an issue like this or is it just more prevalent now that the ride is smoother due to the new tires?

Also, could I have a leak in the caliper piston seal that I am not seeing without taking the whole brake system apart? Can I conclude that I have air in the system?

Any help is greatly appreciated. : )

 

[Pickle-Smooch]

Air in the system is exactly where I would start. I would recommend buying a couple bottles of fresh fluid and bleeding the entire system of any/all existing fluid. Be sure to bleed each position.

 

[RedPepper]

Thanks for the reply. In regards to bleeding the brake system is there a specific order in which to bleed the brakes? Any special sequence or caliper to start with?

I know that some vehicles require you to begin at a certain wheel and progress from there.

Which order did you use?

 

[osiris10012]

Always start at the furthest point from the master cylinder.

Right rear
Left rear
Front right
Front left

I did this exact procedure on mine after changing the front brakes lines. Took bleeding them twice but afterwards everything was great. I had a ton of air because I had a brain fart and connected my new brake lines to the caliper first. I did each caliper 5 times before moving on to the next one. I figured as cheap as brake fluid is may as well be thorough

 

[RedPepper]

Thanks for all of the outstanding info. I really appreciate it.

When installing SS brake lines, what is the correct procedure? I figured you would just disconnect the old ones and install the new lines and perform a brake flush to get rid of the air that was induced. Is this not the case?

You mentioned that you connected your new line to the caliper first and that a lot of air was induced into the system. What is the correct way to install the new lines?

 

[osiris10012]

When installing them you want to connect to the frame side first. This will allow the new brake line to fill with some fluid before connecting to the caliper. I connected it to the caliper first which trapped all the air in the line because it had no where to go and couldn't fill with fluid. So essentially I trapped the amount of air a 25" brake line can hold. Lol. This is why it took my two tries to get the air out of the system.