Front/Rear brakes unballanced after swapping pads

[Craig]

[Skip to ” * ” for the meat of the problem]

-Model Year: 2006
-Make/Brand: Nissan
-Complete Model: Pathfinder SE
-Engine/Transmission/4WD/2WD: 4L(stock)/2-4WD/ All stock
-Country (market): USA (first owner Pennsylvania, second/current owner Michigan
-Part installed: https://www.amazon.com/gp/product/B000S2KZGO/ref=oh_aui_detailpage_o04_s03?ie=UTF8&psc=1 (AC Delco Professional Ceramic Front Disc Brake Pad Set )
-Part replaced: They say “Perfect Stop” on them and look visually the same as the ones I replaced them with
-Previous owner’s involvement in maintenance: Unknown and suspected to be minimal/disinterested
-Car dealership trustworthiness where I bought the car: Shady AF (story available but unlikely to be directly related)

Hello, This is my first post on the forum. With the help of ETCG and other videos, I swapped a frozen front/driver side brake caliper and pads and then did the front passenger side pads a couple weeks later. The process involved sucking out as much of the old brake fluid from the reservoir with a turkey baster and refilling with fresh DOT3 (as printed on the cap and in owner’s manual), doing the required work, bleeding fluid from the caliper (using a 1-person bleed bottle kit) until more clear, and then topping off the reservoir. I did this for both sides of the front.

The first oil I extracted from the reservoir looked like cola in color. I opted to suck out the reservoir again when I did the second side. This time it was about the color of light honey or cheap pancake syrup. I won’t say that my fluid is currently as clear as I will eventually get it, but I’m waiting for an actual hydraulic jack to arrive so that I can have more maintenance joy and less cranking on the ‘oops I popped my tire’ jack that came with the vehicle.

Now, the front brakes are great. I don’t have any complaints there. Nothing is squeeking, shaking, twisting, or any of that and I’m pretty sure that the rear brakes are not critically worn. In fact, the passenger side pads were not that bad, but I wanted them to match the new driver side pads for personal preference. Both front rotors look serviceable and were sprayed down with brake cleaner for good measure. (I saw Eric do this on several drum brakes and figured “why not?”)

* The problem I DO have, is that the front brakes now seem to brake harder than the rear brakes. I suspect that many drivers would not really notice this and so I don’t consider my problem to be an immediate danger. I do notice that it seems to lean forward a bit much after doing the front brakes though, and so I’m seeking an explanation of what is probably happening to cause it. Also, the brakes gradually clamp down and take a lot of travel to do so. They’ve been like this since I got the car and have gradually gotten worse with time. I tend to drive the speed limit or less and let off the gas and coast for a long ways before I use a little brake. I tend to get better than “new car sticker” gas mileage with this behavior and am not in a hurry to get anywhere. After watching the “stomp on the brakes” video, I tried it and it seemed to give me a little sooner brake action, until my driver side caliper seized a few weeks later.

My current ideas are:
– The new brake pads are better at stopping because they are a different brand: But I put on about 150 miles between replacing the left and right pads and the only difference I noticed is that the right side started sounding a little ‘grindy’ until I swapped the right side too. This could be just my heightened attention though and those pads weren’t used up when I took them off anyway. The rear brakes are cooler than the front when I return home, but I expected that since I think rear brakes have less load.
– The back still has old/dark brake fluid: But on a short test drive, how could this really make any difference?
– Brake lines from the hard line to calipers are old or something: This is a shot in the dark, but since my pedal travel is excessive anyway, perhaps I need new final brake lines anyway. I’m contemplating swapping them with steel-braided lines all around, but I’m not seeing any direct replacements for my vehicle. I also don’t want to just do an upgrade to try and solve something that I don’t understand. This is the essence of why I’m asking the community. 🙂
– Spraying brake cleaner on the rotors made them grippy: If this is true, then things should settle back down on their own after a few hundred miles, I suppose. I have only driven it about 20 miles since swapping the second side pads.

I appreciate your taking the time to read this and ponder what may be going on here. I look forward to and welcome your input.

Topic

[Ty]

Not knowing the bleeding procedure for your particular vehicle i would say you still have air in the system.

Also with fresh pads they will grab very hard sometimes until they get broke in.

Another thing. About 70 percent of braking is done by the front and 30 percent by the rear which is why rear breaks don’t wear as fast as the fronts do unless your a very.hard breaker.

[Craig]

Thank you for your input. I suspect that the front/rear imbalance may self-correct as my new brakes wear in and I get some car wash wax and rainy day grime on the rotors. I am also looking into the “brakes have air in them” possible situation.

I just bought a “backup car” today for $500. This should be full of fun maintenance and repairs to practice on. Anyway, searching for an online owner’s manual for it helped me find a few service manuals for my Pathfinder (the subject of this thread) that were previously beyond my search engine skills. Most notably, I found a manual for the braking system.

The brake bleeding procedure is “…front left, rear left, front right bleed valve, in that order.” It doesn’t mention the rear right, but I suspect that to be a typo and that it should follow the front right.

Also found was a diagram of the brake system piping. It shows both lines from the master cylinder going to “actuator” and from that, all 4 lines to the wheels come out. The two rear lines go into one “connector” and both come out of it and proceed to the rear brakes.

Now, also in that manual are instructions for “burnishing” the brakes. This is a similar procedure to the video for slamming on brakes to restore a soft pedal, but the instructions given are to stop from about 30MPH in 3-5 seconds, drive for 1 minute at 30MPH to cool brakes and repeat, performing the sequence 10 times. The instructions for when to do this are described as “…after refinishing or replacing rotors, after replacing pads, or if a soft pedal occurs at very low mileage.”

Now 3-5 seconds from 30-0MPH doesn’t seem all that forceful, and I probably do that now and then anyway. So I’m back to possible air in the lines (if the system corrects for and keeps the brakes balanced so that it’s not as obvious as it was when I failed to bleed my brakes on an ’81 Citation), or perhaps some sort of failure in another component.

There were instructions on testing the brake booster, which I’ll perform as soon as I can. Can a vacuum leak or other problems with the brake booster cause long brake pedal travel? If it helps, I’ve found that pumping the brakes with the engine off gets the pedal to harden up, whereas that is not the case with the engine running. In comparison, the brakes in the 2001 Sunfire I just bought today are forceful and immediately felt with very little brake pedal travel. I estimate at least 10 but probably 20 or more times more travel is required to slow the Pathfinder the same amount. This is going by feel and not measurement, but the Sunfire feels like braking is controlled by force against the pedal while the Pathfinder seems to brake by pedal distance moved. In an incident involving a deer last year, the desired “panic stop” was not achieved, even though I can activate the ABS if I put my mind to it and push the pedal to the floor. Fortunately, I was able to dodge the deer enough that it ran into my front wheel, caused no damage, and walked away. So, come to think of it, the soft pedal is a serious problem, and I’ve succumbed to the “frog in heating water” effect.

[Paul]

+1 for time to wear-in new pads.

Did you replace both front calipers (albeit after different times)?

Are the OEM pads ceramic? Depending on the formulation, ceramic pads can have less initial bite and different pedal feel compared to another pad material. I experienced something that seemed like a softer pedal with an aftermarket ceramic pad.

[Craig]

A quick look at the OEM pad kit doesn’t indicate what they are made of.

I only replaced the driver’s side caliper because it had a stuck piston and the bleeder valve snapped off. The passenger side caliper was serviceable and the bleeder valve was functional, so I didn’t replace it. For what it’s worth, I used Eric’s “push the pistons in with the bleeder valve open” technique and also performed a bleeding procedure on both at the time of service since I had had the bleeder open on one and replaced the other and I wanted to push fresh fluid into them anyway. The service manual for this car instructs to just remove the lid on the reservoir and force the pistons in to accommodate new pads.

I’m not familiar with the different types of pads in use today. I recall back in the day that shops would offer “organic based, economy” pads or “higher performance, semi-metalic” pads at additional cost. The pads I put on, I scuffed with a couple passes of coarse sandpaper before installing and they seemed like they were made of quite soft material. They seem as if they polish the rotor like they were made of soft pencil lead or something. In this regard, they don’t seem similar to the ones that were on the car when I bought it. The high pedal travel was there when I bought the car though, and has steadily gotten worse. Could this really be caused by my gentle-braking habits, or could there be a slow-onset failure happening?

[Author]

Replies