Mushy brake pedal but brakes work fine...

I believe there is a issue with my brakes that I am trying to resolve. Here is a long summation...

I've never liked the pedal travel of my brakes since buying the truck three years ago, though a mechanic I know said the brakes are fine.
This winter, traveling about 50mph at night, I suddenly came upon a herd of elk crossing a two lane highway. I was sure I was going to plow into them as I jammed on the brakes, figuring I would hit several. I did not, stopping about two feet from them and never locking up nor sliding. So the ABS is working fine, or else I would have hit them for sure.
Still the issue of excessive brake pedal travel has bothered me constantly. Last month I decided to re-shoe her and found, when removing calipers and drums that my pads and shoes were barely used. I replaced them anyway and bled the system with my son helping. Test drove it and immediately smelled overheated brake pads - passenger front. I removed the caliper and determined it was frozen in place, so I replaced the pair and re-bled the system. During the whole process I ended up flushing the old fluid and replacing with new. Everything was copacetic except that the darn excessive brake pedal travel was still there.
There are no leaks anywhere in the system and the system was bled properly, twice, with no air being introduced into it.
Anyone have any idea as to why there is so much pedal travel before the brakes engage? I'm talking normal pedal height, then traveling half way to the floor before braking action occurs. She then stops great, no complaint. Is this amount of travel normal?

 

I had a similar experience with my 03 sequoia. All of my calipers and pads were working fine as well as the ABS. But the pedal would travel too far. If you pumped it once it was perfect. No amount of bleeding would help. I even replaced the front brake hoses to braided stainless. But I also had a brake light that would turn on after hitting the brakes the first time every time I drove it. The dealer said ABS module. I just about shit canned the whole truck LOL. Decided to replace the master cylinder with a unit from Napa. It was the only conclusion I can come to besides ABS crap, which I know nothing about. That ended up being the fix for me. All warning lights went away and it stops like a champ!

One thing I learned during my research was, when bleeding the brakes do not allow the pedal to travel beyond its typical motion. Especially on an older master cylinder. From what I read, this can mess up the seals when pushing the piston inside the master, to an area it doesn’t typically travel. So I bled the brakes with a 2 x 4 underneath the brake pedal. Hope this helps.

 

I have also read a little something about the ABS module needing to be actuated through the computer to bleed the brakes properly. I didn’t have any issue with it but I did go and drive the truck hard to get the ABS to kick in after I bled the brakes a little bit. Then I returned home and bled them some more like the OCD person I am LOL.

 

I have begun to suspect the master cylinder, hoping of course that it isn't the ABS at fault. Your info is much appreciated, and I will most likely be acting on it before summer. Thanks.

 

Adjust your Load Sensing Proportioning Valve.

Adjust your rear brake shoes via the star adjuster through the ‘peek-a-boo’ hole so they are as close to the drums as possible.

After doing these things, my pedal feels like there is a potatoe inside there.

 

I’m not one to just want to throw parts at things unless I want to replace them already or they’re failing. But it’s a much cheaper step than replacing the ABS module. I was at a loss at the time and once I ruled out the front brake hoses being collapsed I came to the master cylinder conclusion.

The only thing that’s different between you and I, is the fact that I had the brake light come on because my pedal traveled too far. That’s what finally sold it for me. I figured it had to be. Glad I was right

 

I keep forgetting you guys have drums in the back and the Sequoia is four wheel disc.

 

I don't believe it to be the load sensing proportioning valve as I have no issue with my rear brakes locking up or acting out of the ordinary. Hoping at least, as it is expensive at 600% to 700% markup over a Tacoma or 4Runner's part, or any other brand for that matter. I'm aware that sticker shock applies to auto pricing but I never though it would hit parts as well. Soon one will need to sign a credit contract/app to finance minor parts purchases. Ridiculously inflated pricing - the curse of the Tundra. But then again, she's been trouble free since I bought her at 92,000 miles over 3.5 years ago with odometer now at 120,000. Love that aspect of her.

My brake pedal does act as Sean stated with his rig, with the pumping of the pedal bringing the next stroke up to what I would call normal height and normal pressure. I do sense an ever so slight fade in the pedal pressure if I hold it firmly and constantly at this point, but the feeling is so faint as to possibly be a false sense, psychosomatic - I think I feel it, so I do feel it.

 

Master cylinder has been my experience with a mushy pedal

 

Checking rear shoe adjustment, checking front wheel bearings for play, and bleeding the whole system are things I’d do before replacing the MC.

 

What pads & shoes are you using? This is my 3rd Tundra. I’ve tried aftermarket, but always get the best results with Toyota brand. It’s very important to get the rear shoes adjusted correctly.

 

Mine did the same. First to check is the brake vacuum line system. Starting from the vacuum booster look for splits and cracks in the rubber hoses. I had one hose end going into the intake look iffy, so the end was cut off and put the vacuum hose back on. That worked and brought the brake pedal back to correct brake pedal free play and eliminated the soft pedal. No more having to pump the brake pedal before stopping.
Going to change out all the vacuum hoses sometime this month because they are old and getting hard.

 

Phil and Paul...bearings are good, rear brakes adjusted, new pads and shoes, new calipers, disks are true-no wobble, bled twice, flushed lines and MS and added new brake fluid.
The pedal travel was an issue prior to the brake job and still remains. Rear wheels never lock up or act out of the ordinary and the ABS system works fine. Never leaked fluid.
Haven't checked the load sensing proportioning valve (don't know where it is, either). Haven't checked brake fluid lines because I have no leakage issue. Vacuum lines for what, the booster? hmm
Kinda getting to the point where the master cylinder is my chief suspect. Vast majority of written info and personal opinions are pointing to it.

 

Another vote for rear shoe adjustment. After just replacing my rear shoes/drums/calipers I will say its not as easy as you would think. It will automatically adjust but only if your parking brake is properly tightened. (applying the parking brake moves the adjuster each time until it is tight)

 

Any chance you could give some guidance on how to tighten that rear parking brake cable? I've been wanting to do mine.

 

https://www.tundras.com/threads/im-at-my-wits-end-master-cylinder-issues.39933/

Read up on this if you go with the master cylinder route. An upgrade to 13WL fronts wouldn't hurt. I did that, new rear brakes, and flushed 3 times, but DIDN'T adjust my rear propositioning valve and still have a mushy pedal. They work fine, but I recommend following @Professional Hand Model advice. It takes pressure off the front brakes to let them work better as they can only do so much. That's why your rears look barely used. Because they aren't.

 

If you have access to a complete diagnostics computer there is a function to purge the ABS module of any air (supposedly).

 

I had my mechanic adjust my brakes on techstream. Just made the brakes bite earlier. It feels way better. I too thought it was the master cylinder but he tested it and the MC was fine.

 

PHM...Thanks for the pic. I will be recruiting my son to check it out as I am approaching 69 and way too old to crawl under there.

Roy...I'll keep that in mind as I approach the MS's r&r. In the meantime, my hats off to you guys for the many responses.

 

Sure.

The idea is that your brakes work similar to a lever with a pivot point near one end. This means you can move one end (your pedal) a relative long distance easily, and the other end (your brake pistons) moves a very small distance but with great force. The parking brake does this with an actually lever. The hydraulic brakes do this with different sized pistons, but the principle is the same, a relative large movement on one end, and a very small but very powerful movement on the other.

The complication is that if there is freeplay in the system that large movement of your brake pedal can end up just taking up freeplay instead of applying force. In the ideal brake system the pads are as close to possible to the drums or rotors without actually touching so the instant you press your brake pedal you are applying force to the rotors or drums rather than just pushing the pads through space into contact with the rotors.

The front brakes automatically adjust so your pads are just barely floating over the rotors.

The rear brakes on the other hand have a threaded rod that adjusts the distance between the drums and the brake shoes. There is a little gear wheel with a ratchet mechanism on this adjuster rod and this is connect to your parking brake system. Every time you step on your parking brake a lever moves and tries to turn that adjuster wheel. If there is enough space between the drums and the shoes that lever will move far enough that it reaches the next tooth on the adjuster wheel and ratchets the adjuster rod to reduce that freeplay. It will keep doing this every time you step on the parking brake UNTIL there is not enough space left for the shoes to move far enough to engage the ratchet and your brake shoes are floating just above the drums, this is what you want. With only a small amount of space between your drums and rotors and your pads and shoes you should have a firm brake because instead of your pedal travel taking up lots of slack in the system, its applying pressure almost immediately.

The PROBLEM is, if there is slack in your parking brake cable system when you apply the parking brake instead of it taking up the slack in your brake drum, it takes up the slack in the parking brake cable and so may never get tight enough to cause the ratchet adjuster to adjust properly, and because your parking brake is what adjusts your hydraulic brakes, not only does your parking brake not work properly, your rear brakes never work properly

So, to fix this you have to remove all the slack from your parking brake cable system. I call it a system because it has a lot of parts. Starting with your parking brake pedal there is a cable that runs midway down your truck, which attaches to a intermediate lever, which attaches to another cable, which runs to another lever mounted on your rear axle, which splits to another cable, which attaches to a small lever on the back of your wheel hub, which attaches to yet another short cable inside your brake drum, which attaches to a lever on your brake shoe, which in turn pushes against the brake adjustment ratchet.

But you can ignore most of that. All that you really need to know is that you first take the slack out of the small levers and short cables on the back of your wheels, what toyota calls the 'bellcrank' and then adjust the turnbuckle on the intermediate lever in the middle of your truck ( just behind your cab) so that all the slack is out of the long cables.

This page from the toyota service manual explains how to adjust the bell crank, and once done you simple work the parking brake until the ratchet stops clicking

 

This may also be useful:

 

PHM...Okay, my son went and visually checked its placement (the LSPV) and we discussed its function/operation as a layman might. We have one over-riding question: how do you adjust the darn thing? As he described it to me, and visualizing the valve from Amazon's listing (@$215 - wow!), we see no adjustment mechanisim.

Okay, two questions: And what goes with the rubber boot?

 

You need to get the Toyota shop Repair Manual set, volume 1,2 and 2a, or something like the Haynes Repair Manual to help you get it right.
These manuals are invaluable to the professional mechanic and especially to the layman.

 

02goes...I hear you on the manuals, been wanting to get them for some time, but at $150 for the three-some, and somewhat mangled, to over $250 for new, my social security just doesn't leave enough room. As to the Haynes and Chilton, my experience over the years is that they are a tremendous disappointment as they cram in too many models, over too many years, to be very helpful.
Still, I plan on this truck lasting me until I pass on, so it is an issue that has a high priority right now. I have some recreational property I have put up for sale and I had planned on putting some of the proceeds into the truck. A full set of manuals would be a worthwhile purchase and is a priority item.
In the interim, I have the web - YouTube, has been a solid help in areas that are covered. There are others as well, though I forget their names, partly because they are typically one shot affairs. I am sure this forum will be a great source of info as well, especially because it allows me to speak to owners with experience - something the others lack. Including the official manuals.

 

I'm in the same boat as you as to wanting to upkeep the trk because it's a keeper and soon to be an antique which is unique to me, and all done on the little disability income. Because of being a mechanic in the early years of life I knew to get the Toyota manuals first, and a Haynes for quick general information if I don't need to research the Toyota manuals for the answer.
These books tell ya how to trouble shoot, and unfortunately it looks like you have spent more on throwing parts at the problem than cost of the books.
Good luck with this brake problem and not continue to blindly throw money at it w/o expected resolution.

Can't find a new full volume 2002 Tundra shop manuals cheaper than here.

https://www.summitracing.com/parts/bsk-10508/overview/year/2002/make/toyota/model/tundra

 

Actually the only money spent for unneeded parts was the pads and shoes, a minor cost since I did it myself. The calipers were due for replacement and have eased my mind on their condition, especially since the vast majority of the braking is done in the front according to those who know. I have never owned a vehicle that needed so little repair over 3+ years, so I plan on being a foreward thinking owner and do the preventive maintinance so as to minimize the big repairs. If I can roll the odometer over at 1 million miles, Toyota may swap out a new one in exchange, as they have done it twice I believe. As if I will still be here, if it happens.

Thanks for the link; I always like to shop smart, so I am always looking for a good deal. I will certainly check it out.

 

Some really useful and helpful posts here, especially Aerindal's. I have minimal luck with tightening up the brake pedal on my 05 DC, even after replacing pads and shoes and adjusting the rear drums again and again. The brakes work just fine, I just don't like all the pedal travel before they start to work. I did come across a secret that helps tighten up the pedal - for a while. The automatic drum brake adjust using the parking brake does not work very well and laying on the ground with a brake spoon and spinning the tire just doesn't cut it for me.

Here's what to do:
1) Put the rear axle on two jack stands with both tires in the air.
2) Remove tires.
3) Remove drums.
4) Adjusters are right in front of you now.
5) run out adjusters a little at a time until you just can't get the drum to go back on.
6) Back the adjuster off only one notch and try to put drum back on again.
7) It is OK if you need to tap on the drum with a rubber mallet to get the drum homed.
8) Now do the same for the other drum brake.
9) When you put the tires back on, you should be able to turn the tire by hand even if they stick a bit and/or are a little hard to turn.
10) Put her back on the ground and take her for a spin - what did I tell you? Nice, eh?
11) Any bits of sticking will be gone inside of a mile. *NOW* your rear brakes are adjusted!

Your mileage may vary - make sure you can still turn the tires by hand before taking truck off the jack stands.

Cheers!
Bill