I'm at my wits end- Master Cylinder issues..

Only things I can send are thoughts and prayers. Its so much easier.

 

The Sienna set up requires the infamous unicorn. Same issue as the Tundra set up in that you can only buy the front half of the master and the unicorn only comes with the OEM booster. That’s like a mortgage payment either way, and you’d be as well going with the OEM Tundra parts. The used Sienna rig up (which includes both parts) is too much of a Hail Mary for me too, like buying yet another 11-3300 and praying it works.

 

Add Hail Marys, too!

Unless, Tom Sawyer Remington wants to up the ante!

 

If your repair skills are as feeble as your Google skills, you may be better off taking it too a mechanic...





My master cylinder has not yet failed, otherwise I'd post the how to instructions. I think the Sienna is a drop-in solution but there may be a difference in the piston shaft diameter. I've read or seen both 3/4 and 7/8ths. Given the initial quality of Toyota OEM parts, I would think most here would agree that if you find a used low mileage Sienna unit you'll most likely get several years service from it.

 

From car-part.com



Your concerns that a wrecker yard high mileage unit may fail are valid. That's why I'm suggesting the Sienna unit. If it does fit, the Sienna unit was used up to 2010. Certainly you can find a sub 100k unit from a Sienna. But if you still don't trust OEM used, then you're kinda at the mercy of Chinese rebuild quality or spending $900 for the entire assembly from Toyota.

 

Can anyone recommend me a GOOD shop that specializes in brakes? I don't want just any shop that does the normal removal/replace/install of parts. I can do that myself. I need someone or a shop who can actually diagnose what the problem is w/out suggesting me throw $$ at it. I consider myself pretty handy when it comes to tools and knowing my way around cars. I've done water pumps, timing belt, suspension lifts/lowering of cars and trucks, replaced MC on other cars and the braking issue was solved along with other things and I've also rebuilt engines in the past. I don't know what's going on with this one so I'm just gonna throw in the towel and have a mechanic try to diagnose my problem (if I can find a trustworthy shop).

so far I've
-Replaced front brake calipers, rotors, pads and SS lines
-Replaced rear drums and shoes and adjusted brakes
-Replaced the MC twice (1st was with a used one found at a salvage yard and now a new one (non oem))
-Bled the entire system (in this order; LSPV, rear pass, rear drvr, front pass, and front drvr)

I've tested the booster by doing the 5-6x's pump w/ engine off, while pedal is depressed, turn on the engine and the pedal falls. Booster tested fine.

I'm located in OC, but willing to drive if this guy or girl is all that and more!

 

How do you know if your truck has it or not?

 

If you put your truck in 4x4 a light will pop up on your dash that says "VSC Off"...also, if you go to toyota.com/owners, register your truck and click on view specs...



You should get this page...and if you have it it will show up under Port/Factory Installed equipment...also,
if you know you have physical factory LSD, you don't have VSC. I'm pretty sure they came with one, the other or neither, but
not both.

 

Yay for TRD package and LSD’s!!!

 

Agreed. I'm not the best at repairs, or Googling. I'm just trying to join the dialogue.

I take your point about the Sienna set up being more recent up to 2010, so possibly more better-condition parts available. But I'm really looking to avoid anything used/salvage or remanufactured. I've just had too many bad experiences. I'm also suspicious about why anyone would sell a booster/master combo on EBay if it actually works. I know there may be a number of good reasons why, but you just never know, and with my luck it'd be another squisher.

At the end of the day I'll probably go with the option on post #34. A huge part of the confusion on this thread is due to dealer/online illustrations being woefully inaccurate. If you go on parts.toyota.com there's an actual photo of 472000C073 (which is completely different from the illustration) and that's definitely what I need. I'm not planning paying $1,300 though, so will shop around knowing I have the right part number. Hopefully OEM in the area of $800 will fix this once and for all.

 

Post #34 for refresher.

 

Do what you can with these pictures. The first pic looks like the best deal (and probably most accurate). The second and third pics are the same part from the stealership and the pictures versus diagram conflict. Probs the same thing the parts dept at your stealer sees.

They don’t have the cross reference aspect I present here for you.

 

I recently purchased the part from McGeorge Toyota Online Parts for $875 shipped. It sucks spending that kind of money, the cost of a new set of tires, but the trucks gotta stop.

 

I’m interested, did the OEM part work? Does your truck stop like you’d expect it to, good as new? Thanks for the feedback.

 

Yes, the Toyota part 47200-0C073 which is the complete master/3rd chamber/booster worked perfectly. It comes well packaged and the three main components and short brake lines are all attached. I wasn't experiencing braking issues other than my brake light came on due to low fluid and I discovered brake fluid was leaking into the booster. After replacing the part the truck seems to stop exactly as it did before. No better, no worse. So I would say good as new. Whether or not good as new would make you happy is a whole other discussion.

Hope this helps.

 

Thank you. Very helpful. I think “like new” will be a huge improvement for me.

 

I just joined the forum today. 2 years ago, My MC was leaking into the booster, I bought a replacement from O'Rielly's. I never could get the pedal to firm up, then it failed. O'Rielly's gave me a full refund. then I used a T-100 MC and booster. It seemed to work fine until I had to do and emergency stop. Ended up buying the complete set-up from Toyota for $900. It works like new now.
Before it was fixed I topped off the MC a couple of times to turn off the light. On a steep downhill exit ramp with the brakes applied the engine sucked some of the brake fluid. I thought I ruined the engine, it smoked and ran rough for a couple miles then cleared up.

 

Has anyone had success just changing out the MC from Rock Auto? Got the solid piece one from napa only to find out I have the special one. Just asking that way I don't waste time waiting for the MC when that could be time waitng for the whole booster. But the price of the booster is what is making me just try th MC first. Thank you in advance.

 

Hello all. I'm an auto repair tech and just joined this forum to share my experience with an 06 extra cab SR5 braking system problem. Finding this forum pointed me in the right direction for solving the low brake pedal problem on this truck and I figured I'd post my findings out of gratitude.

In short, I did end up replacing the whole booster/master cylinder/auxiliary master cylinder assembly (47200-0C073) from Toyota to finally fix this customer's truck.

I first encountered this truck last autumn when it came to our shop for an oil change. As soon as I got in the truck and moved it into the service bay I was like "whoa, the brakes on this truck are really effed up!" I wasn't prepared for the pedal going almost all the way to the floor. I asked the customer how long he had owned the truck and, while he hadn't purchased it new, he had owned it for about 10 years. He said that the brake pedal hadn't always sunk so low but it had been that was for a long time.

Since the truck was already on a lift I took a swing at the low hanging fruit and pulled the rear wheels to adjust the brake shoes. They weren't loose so I didn't expect an improvement in pedal travel and I was right. Same problem.

Now the owner hadn't complained about brake pedal travel but once I brought it up he kinda became obsessed with having the situation rectified. He does landscaping work and pulls a trailer so he wanted all the brakes he could get. I was scared to drive the truck empty; i can't imagine stopping it with a few yards of mulch in the bed and hauling a loaded trailer. Yikes.

He made an appointment and at that time I did all the stuff you'd expect. Pulled all 4 wheels, bled at all 4 corners, at the load sensing valve above the rear axle, and at the bleeder behind the master cylinder. No improvement. Then I went further disconnecting the master cylinder and bleeding it separately, also loosening the fittings into and out of the ABS hydraulic actuator. No air found, no pedal improvement. I decided that the master cylinder was leaking at almost 140k miles and sourced a replacement. Same routine with bleeding the master cylinder and everythign else with no improvement. I was getting irritated with this truck.

Another couple of weeks went by, during which time I worked on a Subaru that had a faulty ABS hydraulic actuator and replacing it with a used part fixed the car. I figured for the small investment I'd install a used HCU on the Tundra and see if that solved the problem. You guessed it. Just a lot of wasted brake fluid.

It was about then that I went to Google and looked for hits under "tundra low brake pedal" and as soon as I saw the thread titled "I'm at my wits end..." I knew that I had hit paydirt. The customer wasn't thrilled about spending $1200 plus labor for the booster/master cylinder but he did want decent brakes so he gave the go ahead. If I wasn't already convinced that this issue was a real problem with first generation Tundras I sure was when the local Toyota dealer told me that the part was in a local warehouse and I could have it the next day. Seriously? A manufacturer doesn't stock a part like that in local warehouses for a 15 year old truck unless there's a PROBLEM with that part.

Sure enough the part arrived the next morning, I installed it, and *BOOM* I had a good brake pedal. Unbelievable.

As part of the diagnostic process I tried to trace the brake tubing and figure out what was going on. Yikes. Never seen such convoluted brake plumbing. It seemed like one port of the master cylinder was feeding both front and rear circuits while the other port was feeding, well, I don't know what... And that tee in front of the booster, not to mention the thing between the booster and the master cylinder... What was that???

I had read the posts saying that the mystery part was not available separately and only available as part of the booster assembly. Why? I could be more adventurous with the old parts once they became scrap so I started taking thing apart. Or trying to... I learned that you can remove the two nuts holding that mystery component to the booster but the mystery component won't come off the booster. I guess there's an internal connection to the front of the booster shell. I may investigate further later.

More importantly, with the booster off the truck I could see something inside the mystery component and wondered what it was. I was able to extract it and found what I believe to be the source of the whole problem. All this aggravation and expense for a failed lip seal.

 

Nice detective work and write up. Thanks for the pics.

 

1. What do you have to do to get to it?
2. Any idea what that seal is/called/size and how do I get it?
3. Can it be replaced or is it too much of a pain?

Thanks so much for posting. A majority of the time my brakes feel almost adequate (cold warm ups) but after a short time of driving and after warm up theyre as firm as a liberal's handshake.

 

Sometimes resurrected threads are a God send, thanks for your story !
Welcome and please drop by when you can with more 1st Gen Tundra stories. Sponging up info before I forget what kind of truck I have is appreciated !

 

To Somemedic:

Note that the truck I was servicing is a 2006 so I don't know if the brake system is the same for your truck

Accessing the seal is super easy albeit messy. All you do is disconnect the two tubing connections from the front master cylinder and then remove the two nuts/bolts that hold the front master cylinder to the rear master cylinder (aka mystery component). Then you pull the front master cylinder from the mystery component at which point all the brake fluid in the reservoir gushes out onto the inner fender.

This is something I should have mentioned in my first post as it was my initial clue that I was not dealing with a "normal" braking system.

The Tundra front master cylinder does not have a flat back that mounts to the booster. It has a stepped boss with a large 2"ish 0-ring, a narrow space, and then another slightly smaller o-ring. The narrow space between the o-rings has several radial holes drilled in it and these, apparently, go straight to the reservoir. A long (6"?) pushrod/piston then slides into the front master cylinder bore. I'll snap a pic at the shop next week and post it.

I THINK what's going on is that the mystery component is actually a sub-master cylinder that is used for the rear brakes. So fluid in the reservoir flows through those radial holes to supply the sub-master cylinder. Hence the gush of fluid when you disconnect the two.

Once you do separate the front master cylinder from the sub-master cylinder you can look into the sub-master cylinder bore just as I show in my picture. I used my handy dandy Blue-Point "Chinese fingers" to extract that small piston/seal assembly. It will come right out no problem.

I wondered if that seal was available separately. I saw mention early in this thread about a master cylinder seal kit from Toyota selling for something like $75. I looked into buying one of those seal kits. Unfortunately every listing for that kit fails to include a picture of the contents. Who wants to find out? Volunteers?

 

Here’s a shot of the rear end of the forward master cylinder. Never seen one like this before…

 

Does Toyota have a master cylinder rebuild kit available for the NON VSC master cylinder shown in post 116?
Because it seems insane to have to buy the complete assembly just to get the $50 part that actually needs to be replaced.
Ive been searching and have found Toyota OE master cylinder repair kits but I haven't found one yet for the NON VSC master cylinder.

 

I'm not seeing one for your year when I look. I ordered a master rebuild kit from Toyota for my 02 and once I got my master apart it was clear that whatever they sent me was completely wrong. Here is what I ordered.

Part Number Part Name Price Quantity Total
04311-34020 Master Cylinder Repair Kit $34.32


Here is what the old vs new looked like. Completely different.

 

Thanks for posting up pics of that Toyota Master cylinder rebuild kit for reference.
I haven't taken mine out yet but will be today.
The other issue to consider is which side of the master assy needs to be rebuilt and if its the seal shown in post 110 then there wont be a rebuild kit available because that is part of the unavailable "unicorn".
I'm leaning towards the rebuilt Cardone 11-3300 as long as it includes the "unicorn" but the feedback on that part certainly is not reassuring from this thread...
Its either that or the whole danged assy 47200-0C073 just to replace that seal that is shown damaged in post 110, I have to say this thread was aptly named...

 

I ended up gambling on the Cardone 11-3300, hopefully QC has improved on these rebuilt master cylinder assemblies AND hopefully it actually IS an assembly that includes both halves as the pic shows...
I'm not really sure which half of the Master cylinder is leaking so thats another reason I gambled on the Cardone rebuilt unit. I didn't see any brake fluid in my booster and the seal was not torn or disfigured in the "unicorn" section so I'm not really sure whats failed. I'll update this thread with what I find and my feedback on the Cardone rebuilt unit too.

 

This is an initial follow up to my purchase of the Cardone 11-3300 rebuilt master cylinder for my 06 Tundra Doublecab without VSC.
I purchased it from carparts.com for $140 which included the $20 core charge. The 11-3300 master cylinder does include both halves of the master cylinder as shown so that was a big draw along with price and that Cardone appears to be rebuilding from Toyota OE castings not cheap knock offs. If I could have found a rebuild kit for both sections of the master cylinder I would have gone that route but I never did find the correct rebuild kits for it. I've only had it on my truck for a couple of weeks so I can't comment on the long term quality but initially I am very happy with it and my brakes are functioning again!
The only issue I had with the Cardone 11-3300 was that the provided brake line that connects both halves together is incorrect for my truck in that it is bent differently and my original reservoir doesn't clear it...
So I just cleaned up my original line and swapped it in, not sure why that line was different but the rest of the unit is identical and the brakes feel and work the same as before my original failed so Im good with it.
If I have issues down the road I will feedback because I really appreciate all the info I got off this thread!