# Newbie with a major brake issue



## kentrodngun (Aug 22, 2016)

Hi guys, got a real stumper. My brake pedal goes to the floor, I can't pump it up, so I assume no air in the system. It is a 2004 Nissan Frontier Crew Cab 3.3L.
So, what have I done? 
New calipers & new pads in the front.
New wheel cylinders, new drums, new springs, new brake shoes in the rear. 
Bled it probably 20 times using a vacuum bleeder. Still no pedal. 
Replaced master cylinder (yes, bench bled), no change. 
Replaced brake power booster, no change. 
Reinstalled the old master cylinder (yes, bench bled again), no change and yes, I bled the system again at least 10 times.
I tested the ABS motor - runs. ABS unit gets 12 volts, all fuses tested and good.
I looked to see if the truck has a proportioning valve - it does not.
I've ordered an Anti Lock Brake Unit ABS Pump Actuator Assembly as my last resort.

I have little hair left from pulling it out. Can anybody help? Dealer next if the ABS unit doesn't do it.


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## Cusser (Apr 16, 2004)

ABS only does anything when pedal slammed during a panic stop, so unlikely involved in this.

Before you did ANYTHING, what were the SYMPTOMS. 

You did a lot to the truck, yes there is a lot of air in the system from the new master cylinder, calipers, wheel cylinders.

Did you adjust the rear brakes MANUALLY before you started the bleed process? That's a must. Then you must get out all the air by bleeding, and if you have 4WD with load sensing valve, then bleed that too. Even a little air left in the system can make the pedal go to the floor, and your inability to pump up the brake can just indicate lots of air.


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## kentrodngun (Aug 22, 2016)

Thanks for your reply. Yes, I adjusted the rears with the brake spoon prior to bleeding the new wheel cylinders.

When I got the truck, the pedal was low. Initially the pedal felt good but after starting it, it sank to the floor. Did this every time - firm pedal when off - dropped when engine started.
I checked the calipers and found the pins were frozen in place. Vise and channel locks couldn't move them, so I bought calipers & pads, bled all four wheels and still had a lousy pedal. 
Rear drums looked terrible so I ordered new drums and since it is a minor expense, bought shoes, springs & wheel cylinders. Vacuum bled the entire system (RR, LR, RF.LF) multiple times - no improvement. Just to be sure, I had someone do it with me the old fashioned way - pump, hold, bleed (using clear tubing into a bottle filled with brake fluid). Perfect, no bubbles - did it 5 or 6 times per wheel. Always fresh fluid (I'm closing on a gallon now).
Next bought a new MC and bled it using clear tubes - long time but finally no bubbles, installed and bled entire system (as above, using both methods) multiple times. Next was brake power booster, same bleed protocol again.

Sorry for the long reply but I want to be precise. I've worked on cars and brake systems for 45 years and have never had a problem like this. I need to go back to the days of points, rotors & condensers (wink, wink).

Finally, where is the load sensing valve located? and what is that bleed procedure?


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## kentrodngun (Aug 22, 2016)

Just checked out other threads on the site and discovered only the 4 cylinder has the load sensing (Nissan speak for Brake Proportioning Valve). I have the 4WD 3.3L V6 and it is supposedly built into the Master Cylinder, so sadly that fix is out.


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## Cusser (Apr 16, 2004)

kentrodngun said:


> Just checked out other threads on the site and discovered only the 4 cylinder has the load sensing (Nissan speak for Brake Proportioning Valve). I have the 4WD 3.3L V6 and it is supposedly built into the Master Cylinder, so sadly that fix is out.


Did you download the factory service manual for your 2004?

My daughter has a 1998 Pathfinder 4WD 3.3L V6, and it DOES have a load sensing valve, I've bled it; on that it's in the center, underneath, at the rear. But I have a 2004 Frontier (not 4WD) so I looked at its brake section, and by 2004 there is no load sensing valve. Apparently the 2004 Frontier with 4WD and manual transmission has an ABS module and 2004 Frontier with 4WD and automatic transmission has a VDC actuator, each coming off the brake master cylinder. 
From that service manual:
Bleed air in the following order.
– Left rear brake
– Right rear brake
– Left front brake
– Right front brake
– ABS actuator/VDS

If you supply your E-mail address here or in PM, I can E-mail the brake section of the 2004 service manual, it's about 1.5MB in PDF.


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## kentrodngun (Aug 22, 2016)

Cusser, thanks I have the both brake service manuals (Brake Control Service Manual & Brake System Service Manual). I've been reading them for weeks, trying to figure this whole thing out, to no end.

The bleed order is contrary to what I've always done. RR is usually first as it is furthest from the MC, the LR then RF, again it being further from the MC from the final LF. But I see in the service manual what you quoted. I guess Nissans are different (this is my first one).

Although I have the 4WD, I do not have VDC, it was optional - I do not have the button or dash lights for it. I wish I had it as the vehicle slips and the VDC would help correct that situation.

I'm kind of hoping the replacement of the ABS unit will shut off the ABS dash light and maybe correct my problem, but at this stage, I'm not overly confident that will happen.


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## kentrodngun (Aug 22, 2016)

Quick update - I changed out the ABS unit and triple method (vacuum, pedal with helper & gravity) bled the system multiple times. No luck, still at about 10% braking power.

I finally cried uncle and took it (very carefully) to the Nissan Dealer today. They did a recall job on the steering column and spent 1/2 hour looking at the brake problem with no solution. I authorized another 1/2 hour and again nothing. My fear is they will get me up to $300 in a heartbeat and still not discover the problem, let alone correct it.

Stay tuned. I will let you all know if this gets resolved.


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## rogoman (Dec 16, 2004)

Here are some thngs to check:
The port that the bleeder screws into needs to be at the top of the caliper piston, so that an air pocket cannot sit in the piston above the bleeder. If the bleeders are not in the correct position, you probably have your calipers on backwards and can fix the problem by switching driver side caliper to passenger side and vice-versa. If you have your calipers on correctly and have bled all of the air out of the brakes, then the next step is to check to make sure the booster rod is the correct length (power vehicles only). The rod that comes out of the brake booster and enters the master cylinder needs to be almost making contact with the piston of the master cylinder, but not pre-loading it. You want as small a gap between the booster rod and the master cylinder piston as possible.


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## kentrodngun (Aug 22, 2016)

Calipers were installed correctly - no air in system. Nissan Dealer did a visual on the entire system as a start. I've heard of broken booster output pushrods causing problems like mine. I did mention to the Tech earlier today to please check to see if the pushrod was within spec. Hope that is the issue. Thanks for your comments.


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## Cusser (Apr 16, 2004)

kentrodngun said:


> I finally cried uncle and took it (very carefully) to the Nissan Dealer today. They ... spent 1/2 hour looking at the brake problem with no solution. I authorized another 1/2 hour and again nothing.


Hmmm - Nissan dealer is supposed to have expertise, and can't find the issue? Especially since the pedal still goes to the floor? You should not be paying for their guesses. Whether a dealer or an independent shop, make sure there is an agreement that you will pay for a fix, but not for a guess. A few years ago a GM dealer gave up on trying to fix an intermittent sunroof "failure to close" problem, but I had told them I'd pay for a fix, but not for a guess. GM told me they "had no idea what was wrong". GM did refund my $220 for the replacement switch and their labor, but of course that was a hassle too.

The legal term for this is unjust enrichment, so if you're paying for a guess, then it's your problem. But if the agreement is to pay for a fix, then they can't have your $$$ and not provide their end of the bargain. I think I'd try independent shop, or brake shop. The trucks have brakes very similar to other vehicles.

One question: my 2004 truck has rear drum brakes; you did adjust the rear brakes manually before your bleeding, correct?


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## kentrodngun (Aug 22, 2016)

Thanks for the advise, I will speak to them this morning. As to whether I adjusted the rear brakes prior to bleeding, yes I did.


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## kentrodngun (Aug 22, 2016)

So call from dealer said lines were clear - no air, but he took off the master cylinder and the brake power booster. He said he vacuum tested the booster and that it would not hold pressure. They suggested changing it out ($432) but I said I'd rather take the vehicle and return the faulty booster since they would not guarantee that the problem would be solved by changing the booster. Bottom line bill at the dealer was under $100. RockAuto (1st problem I've ever had with their parts) has provided a return label and will ship another unit upon receipt of my defective one. The dealer tech he will note on the bill that he tested the unit and found it defective. I'd rather change it out myself and find out if I still have the problem and save $332 in the process. Hard to believe my original booster and the new one were both bad. Boosters rarely go bad. Stay tuned - next update in a week or two.


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## kentrodngun (Aug 22, 2016)

So, the Nissan dealer said the brake power booster (a replacement) was not holding pressure. They offered to change it out ($432) until I said, "If it doesn't work, there's no charge, right?" They declined and I took it back home. I called Rockauto and told them the dealer said the replacement booster was defective. They sent me a return label and shipped a new unit. 

I installed it today, bled the master (beautiful flow - no bubbles) and bled the entire system again, in the service manual order. Perfect clean fluid, great flow, no bubbles. My helper said the pedal felt great. I said start it, it'll probably sink like a rock. It did, right to the floor. Giving it quick, short pumps will give you about 10% pedal, just like before, but it's not enough stopping power to take it out on the road. Without pumping, there is zero pedal. I am defeated again. 

Anybody have any suggestions? and please read the above posts before offering to do all the things I've already done.


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## poikää (Sep 6, 2004)

Check vacuum line to booster also any check valves. Look for collapsed hoses. Did you adjust booster actuator rod length? Lastly and a long shot.... the callipers are symmetrical so it is possible to switch sides by mistake, I've seen this happen to a Dodge pick up a few years ago. The bleeders will wind up inverted and the callipers will retain air.

GL poikaa


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## kentrodngun (Aug 22, 2016)

Check valve in vacuum line is fine (3rd booster) hose is perfect. No other collapsed hoses. Rod length was adjusted. Calipers installed correctly. Thanks anyway.

I am now in month five of ownership and have yet to drive this thing although I am considering off a cliff or into a lake or the ocean.

Quick update: 
I was still getting some air on the drivers side front caliper so I replaced the hose and hard line. Bled perfectly after that, but no luck. My classic car buddy stopped by and observed that the ABS actuator is mounted way above the master cylinder, so he suspects air is trapped there. I previously mentioned to the dealer that they might need to bleed the ABS using their diagnostic hook up, but they had no idea what I was talking about (I'd read about this on other blogs). My buddy had me bleed the ABS with him but again, no change. Great pedal, start it, no pedal. UGH! Logically, since everything's been changed, it has to be trapped air.

As a last ditch effort, I've ordered a reverse bleeder from Ebay and will pump fluid from each bleeder forward in the hope that any trapped air will be pushed through the line, through the ABS and into the master cylinder. Fingers crossed!


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## poikää (Sep 6, 2004)

I would suspect the booster is applying it's power to a system that has a mechanical disconnect. This guide has a few pointers that you may want to go over.... https://carmanuals2.com/d/47093

This guide has a few static tests you could check to eliminate problems by dividing and conquering. Also measurements of the booster rod and some no no's.... Be sure the master cylinder is correct, that is the pistons are in the right order and the cups are facing the right way. Simple stuff for sure but anything can happen. Wish I could be there!

poikaa


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## kentrodngun (Aug 22, 2016)

Thanks so much, but it looks like my Frontier Service manual. I have reviewed both the Brake Control and Brake System sections and have done everything suggested short of the diagnostic tests as I do not have the equipment. I will stop and chat with the service guys at another Nissan dealer tomorrow and see if they have any ideas.


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## kentrodngun (Aug 22, 2016)

Finally solved!!!!

I did the reverse bleed and still no improvement. My tech buddies and two dealers suspected the brake power booster but as you know, I replaced the original booster and when the dealer said the replacement wasn't holding pressure, RockAuto sent me another - no improvement.

My brother said why don't you try one from the boneyard? So today I went and pulled a booster from a 2002 Nissan Xtrerra 3.3L (interchange said it would work for my 2004 Frontier). It only cost $21 including tax and I figured, why not? its only $21. Put it in, reverse bled and voila! BRAKES.

What a nightmare, but its finally over. Hope this helps anyone else experiencing this crazy problem.


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## Roader (Nov 9, 2014)

What brand were the two failed boosters from Rock Auto?


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## kentrodngun (Aug 22, 2016)

A-1 CARDONE 536009 {#472101Z860} [Power Brake Booster] Reman. Vacuum Power Brake Booster w/o Master Cylinder Info 4WD 

RockAuto only offered a choice of RWD or 4WD for the booster. When I checked car-part.com (salvage parts) they also had a choice of VDC or non-VDC. Mine is non-VDC, I wonder if the 536009 Cardone unit was for a VDC equipped model? 

Regardless, neither unit worked for me and cost me months of work and aggravation. 

Thank goodness I finally cured the problem, now I can invest more money into new drilled & slotted rotors and new rear backing plates.


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## Cusser (Apr 16, 2004)

Cardone also sells through O'Reilly and others. I believe I have one of their boosters and power steering pumps on my Mazda B2200 truck, have been fine.


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## Roader (Nov 9, 2014)

I've had pretty good luck with Cardone too. They seem to be one of the better rebuilders. The only problems I've had was a leaky master cylinder on a Ford pickup and an axle shaft that started clicking after 10K miles or so on an Accord. Advance Auto replaced both under the lifetime warranty. Gotta save your receipts.

Reading through this thread, parts that don't often fail are maybe better replaced with a used, junkyard part vs. a rebuilt part from an auto parts store. That way you get OEM quality at a good price.


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## Cusser (Apr 16, 2004)

Roader said:


> Advance Auto replaced both under the lifetime warranty. Gotta save your receipts.


We don't have Advanced here in Phoenix. Autozone and O'Reilly track your stuff by your phone number, but I do save my receipts, and I add my maintenance and repairs to a logbook.


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