Mushy brake pedal but brakes work fine...

I notice that no one has brought up bleeding the ABS module. I have done everything I can imagine except adjusting the load sensing proportioning valve, replacing the master cylinder, and bleeding the ABS module. There is zero loss of fluid in the system, so I am currently ruling out the master cylinder. I don't see how the LSPV would effect the pedal travel. And I have come across a few too many comments, elsewhere, that suggests the need to bleed the ABS module. So...

Next month I will be buying a scanner with the ability to auto bleed the ABS module. I just bought a 4K action camera and accessories, which leaves me short this month, but I could swing the ~$250 next month to buy a minimalist unit. My hope is that Amazon will offer up a discount before hand. Hope, hope.

 

I wasn’t loosing fluid either. But mine ended up being the master cylinder. Fluid doesn’t have to be lost for it to fail.

 

"I am currently ruling out the master cylinder." Subject to change, of course. My thinking being I could use the upscale hand scanner regardless of the outcome here. I do have several other vehicles that I wrestle with on occasion that I could use to read codes, etc. Were I to get the master cylinder, and it not fix the pedal travel, then I have not progressed except for the assurance that the MC is new and unlikely to fail anytime soon, Murphy be damned. On another level, it makes it easier to convince the spouse that I need the scanner, that were I to suggest otherwise, and without a justified need, would cause her tongue to waggle unwaveringly.

 

Did I miss if you have new brake fluid in the system? DOT3?

 

A code reader is good to have regardless. So that’s a good move. If actuating the ABS with the scanner doesn’t fix it then you could move on, but you didn’t lose ground because you still have a handy scanner LOL

 

3.7”? Thats what she said.

Seriously, 3.7”? Whats this mean?

Edit: How many clicks adjustment were made by your son at the ‘Star Adjuster’?
Depending on your drum wear this adjustment needs to be made after your drums are installed over the shoes.

 

I want to say 3.7” of free play means, from pedal resting position, to depressed position at 50 ft lbs

 

I’m going to measure mine for sure and test this spec later. Seems pretty long of a distance.

 

Yeah it does. But 50 ft lbs is a good amount of force. I wonder how the hell that could be measured. Get a torque wrench out and set it to 50 ft lbs. put it on one of the lugs of the wheel and push until it clicks. And then your best guesstimate on the brake pedal LOL.

 

We flushed the system using standard brake fluid - DOT 3. Further, when we adjusted the drums we adjusted until they wouldn't turn by hand, then backed off until it would turn, but not free wheel. I've done a lot of drum brakes in my past, master cylinders, wheel cylinders, a few brake boosters, but never any ABS systems. I'm not new to wielding a wrench or two.

And I found the scanner that performs the ABS bleed for sale on AliExpress for $80.50 shipped free, $88.50 with molded case, leaving Amazon and their $140 in the dust. A slow boat from China, but I can wait. The scanner is far cheaper than any shop rate to bleed the ABS.

As to pedal throw length, mine is at least 5 inches, possibly 6, before I feel any resistance.

 

Definitely keep us updated with the outcome. My money is still on master cylinder. But I definitely wouldn’t rule out the ABS. When I was in your same shoes I was very frustrated.
One more question for you. Is the pedal travel better if you give it one pump when the truck is running. Because that was my symptom.

 

I honestly thought the mushy pedal was normal for our trucks based on the responses from others. Are we saying it's fixable?

 

Yes, the pedal travel lessens considerably after a pump or two. If I then let up entirely, the pedal travel again becomes excessive until a pump or two. Repeat as needed, your mileage may vary, and batteries not included.

 

Ok. I just measured my pedal.

With engine on, the pedal measurement from floor carpet to top of pedal where your foot makes contact is 5 7/8”.

Put truck in gear and coasted and then pressed pedal till full stop potatoes (hard resistance) and the pedal distance closed to 3 7/8” distance. A difference of only 2”.

Measurement taken perpendicular from pedal to angled portion of floor board. Used a hard ruler and pushed into the carpet slightly. Repeated multiple times. No change in the 2” difference.

 

LSBP Valve is such an easy adjustment. Surprised you haven’t tried it to rule that out. Takes about 30 seconds and free. Move those nuts up 3/4”. Drive it. Report back.

 

How many ports on your master cylinder?

Just the 2?

 

PHM...I could swear my foot traveled at least 5 inches before resistance. Ruling out that 5, a measured guess of halfway to the floor is still within my comfort range on a guesstimation.
With the info you provided (running on faith, here) I will adjust the valve as soon as my son lets me have my rig back. The reason I didn't tackle it sooner is that the illustrations on adjusting the valve depicted two hand held vacuum/pressure gauges, of which I have none.

landphil...The truck's not here, so I am unable to count the teats. But, I believe it to be two with lines out and an additional on the bottom that is plugged.

 

So if just two ports on the master cylinder, here's my next suggestion. Buy a short steel brake line with the appropriate fittings, bend it to make a loop to go between both ports of your MC. Remove the existing lines, install your new temporary jumper line and bleed it by loosening one fitting at a time while someone depresses the pedal. You are essentially dead-heading the MC, without the huge hassle of trying to find plugs to fit your MC. The looped line accomplishes that, and should cost you less than $10.

Run the engine, and see how that pedal feels now. If your MC is good, the pedal feel will be solid beyond your wildest dream. If it's still spongy feeling, your MC is bypassing internally.

Bleeding the ABS modulator unit is a good idea as well. Really the only way air can get trapped in the modulator is when the hydraulic circuit drains completely or the modulator is removed. I'm understanding that your issue goes back to before you owned the truck, so maybe that happened.

 

A bit of research shows the two ports should be M10x1 thread using a SAE / inverted double flare (not bubble flare). Common and easy.

 

landphil...It has nagged at me ever since doing my truck's brakes and bleeding them, that I believe we used to bleed the MC back in the '60s. What you say sounds good, but couldn't the MC be bleed by removing the plugged port on the bottom of the unit?

I appreciate all the input you guys have given and I am certain a way will be found soon enough, but don't go looking for me to resolve it too quickly. My May has suddenly been booked with doctors and hospitals. Hopefully I will be good to go in June. My mind is strong, and I will be busy accumulating the knowledge to approach this issue of pedal travel when I am fit to go.

 

I just got word from the Chinese broker that the ABS auto bleed scanner I've been pitching is a no show, they only go back to 2003 on Asian vehicles, leaving my 2002 out in the cold. I so wanted to circumvent the shop man. So it's LSPV and MC for the time being.

 

I don't if it means anything....but for what its worth there is no mention anywhere in the toyota service manual of ABS bleeding.

 

Would this work?

 

Yup, as long as the fittings match up. Might be more expensive, but easier than a steel line.

 

Those who have followed this thread might have guessed that I was hung-up somewhat with the ABS actuator assembly being at fault, and rightfully so. Although I have still to fix the issue, I have come across a video that pretty much illustrates the issue from my point of view. I hope it is cool to leave a link for the purpose of passing on such info - https://youtu.be/ceN0a-nPUZw

 

I've come across another scanner that purports to read ABS, SRS, etc., codes on model year 2002 Tundras, per an email from one of their engineers late last night. The scanner is a small little affair called the BlueDriver (currently at Amazon for $99.99) which fits in a pocket, and is used when linked to a smart phone. Now although the engineer stated that it reads the codes, he never stated that it will bleed the ABS unit, and I am waiting for such a clarification should he follow up my further inquiry with an answer.

$100 BlueDriver Bluetooth Pro OBDII Scan Tool for iPhone & Android

BlueDriver Bluetooth Pro OBDII Scan Tool for iPhone & Android

$100 BlueDriver Bluetooth Pro OBDII Scan Tool for iPhone & Android

4,192
$99.95
__________________________________________

There may be a copycat on AliExpress (looks identical and calls itself BlueDriver as well) that sells for around $25.20, shipped free to US. Yes, Han has been busy.
Blue Driver OBDII Code Reader Automotive Diagnostic Scanner OBD2 Bluetooth 4.0 JDiag

Alldiagtool Online Store
US $25.20 / piece
Free Shipping



It remains to be seen if it is in fact a true copy, with all the functionality of the unit Amazon sells for four times as much. And note that I wouldn't rush out and buy it if I were you, as there might be problems when you try and upgrade the software on the Chinese unit. Is it a counterfeit? Or a rebranded unit from the factory making the original? Since I brought it up, I will try for answers should Han want to play, and report back ASAP.

Oh, and if I am breaking any rules by posting in this manner, please speak up politely and I will certainly remove it.

 

Well their engineer got back to me with an answer, not that I like it.

"At the moment we perform passive diagnostics only, we will be looking at bidirectional communication which will allow us to write data and send commands to the vehicle in the future, but there aren’t currently any timelines for when this might be done."

Bottom line...Don't hold your breath waiting.

 

$169 Autel MaxiCheck PRO AutoBleed Scan Tool, ABS Brake Bleed with with ABS SRS Diagnostics, Full OBDII, BMS EPB SRS SAS Oil Reset Services for Specific Vehicles, Free Update, Functions Not for All Cars

Autel MaxiCheck Pro OBD2 Scanner

I sent an email to Autel, asking whether or not their MaxiCheck Pro scanner would auto bleed the ABS actuator on a 2002 Tundra Limited, and here is their reply:

"Thank you for your email. Autel engineers has just confirmed that MaxiCheck Pro should be able to auto bleed your vehicle 2002 Toyota Tundra Limited TRD 4wd with 4.7L engine.
Please be reminded that your purchase with us is 100% risk-free as this item is backed by 45 Day Money Back Guarantee and 12 Months US Seller Warranty."
___________

This scanner on AliExpress is running around $196 and free shipping. On Amazon it is running at $216.99 and free shipping. The prices are so close that I would buy from Amazon, with their better return policy and quicker turn around. Just saying...

 

Have you thought about getting one of the Techstream deals?

Not endorsing this one but just as an example.

LZLRUN Mini Vci Interface for Toyota J2354 Tis Techstream Diagnostic Cable Toyota Firmware V1.4.1 https://www.amazon.com/dp/B06XGB714M/ref=cm_sw_r_cp_apa_i_pkv2CbA73H8SK