Might have a solution for Tundra Brake Problem.

I may have finally found a solution for the inconsistent and unusual First Gen. Tundra brake pedal feel. For me the pedal feel it was as if it the pedal was not firm and often would exhibit a feel like it would require a "primer" pedal push first and then the pedal and brakes felt reasonably responsive but no where near what I felt they should be. It has taken me a period of months of trial and error and even local independent shops could not find the fix or they deemed the brakes "acceptable".

I have owned this truck since new (2002 Limited A-Cab with only 82k miles). As others, I have gone through rotors, shudder, pads etc. which would work for a while but not completely proper. I finally did the 2004 Tundra "WL" upgrade with PowerStop calipers, rotors and Z36 pads with proper bedding but something still was not right and I didn't have the full first brake application confidence I desired. I tried a shotgun approach with new stainless flex lines, new rear drums, shoes and wheel cylinders, changed out the proportioning valve, many multiple brake "power bleeds" (read gallons!), repeated rear brake checks/adjustments etc. I was at wits end at not being successful with getting a firm pedal and feel at the first brake application. It appeared as if maybe the only thing I hadn't changed was the brake master cylinder was the cause. Until -

I found a article from a brake trade publication about the Toyota Tech Tip: Inconsistent Brake Pedal Feel which also referenced the Toyota TSB for the Toyota "new style" anti-squeal" two part shims (part number 04945-35120). I ordered the shims and was about to do the install when I noticed slightly less pad wear on the inside driver-side pad compared to all the rest. Could it be the problem? I contacted PowerStop (really great people!) who immediately shipped new warranty calipers, new pads, new rotors, AND EVEN REFUNDED ME FOR THE TOYOTA SHIM PURCHASE! They said it might be a possible faulty caliper so lets replace everything. Everything went smooth and I started with just the new shims (both side) and one new replacement caliper on the driver side for trial and with yet another power brake bleed for "shits and giggles". Holy crap I had the responsive brakes I was looking for with no other changes.

I then replaced the other caliper, both rotors, the new pads with the "new style" Toyota shims, another brake power bleed and proper pad bedding. I can't get over the difference. I haven't had brakes this good since new, perhaps even better than new! Incredibly the unladen truck stopping power is on par if not better than my 2019 Platinum. I am so pleased with these brakes and thought maybe I could save someone a bit of aggravation. In summation I think it was a slight sticking "new" caliper and the lack of the Toyota new style two piece shim kit that was the culprit all along. Sorry for the L-O-N-G Post but I am jumping for joy! Thank you PowerStop for your incredible warranty help and assistance.

As a PDF attachment please find my copy of the mentioned Toyota TSB. As it is from 2006-2007 I expect this is OK to post. If not can the mods please delete. Thanks!

 

Super helpful information. Thanks for that.

You need a party hat and a cake!

 

What is this shim and where does it go?

 

You have pics of your work? I like pictures.

 

Going out on a limb but I’m going to guess it goes between the piston and the pad to shim the pad closer to the rotor.

 

I also think our brakes are no bueno, with an occasional “stutter” near full stop, even after new front pads, and rears. But I’m confused; you needed shims on one side, not the drivers side tho-? Yes, please, will you post pics?

And thanks for sharing what you figured up!

 

Well now I'm sad.

 

049450C030 replaces it.

 

As @Scuba mentioned...."between the piston and the pad to shim the pad closer to the rotor"

While the below TSB pdf pertains to a 4runner, the part # 04945-35120 matches what Skip mentioned above. Finding past Toyota TSB's are daunting at best. Will be visiting dealer thur for 2017 Highlander main and will ask Keith their Master Tech if he can get me the this TSB for 1st Gen Tundras.

 

True

https://parts.toyotaofcoolsprings.com/oem-parts/toyota-shim-kit-anti-squea-049450c030

 

Couple of KISS observations:

1) The shim puts the pad closer to the rotor so the distance the piston needs to travel is less making the brakes respond faster. But why is this called an anti-squeal shim? What happens (to the magic fix) when the new pads wear down? How thick is this shim?

2) Anyone here grease their brake pistons? Does it help?

I drive a 2002 and the pedal is soft (compared to other vehicles), but the truck brakes/stops pretty well. The LSPV adjustment made a large difference is stopping power. Overall, I’m happy and will not touch my brakes unless someone confirms this shim fix. Most of these brake problems/fixes I read about on forums dating back 10-15years never were resolved. Lots of ‘soft pedal’ and ‘stainless braided lines’ talk but no real fix.

Hope this shim wow fix isn’t a sham wow.

 

The referenced shim kit was from a TSB bulletin and was reposted in a site called "brake and front end". The official Toyota TSB is difficult to locate without a subscription service but it is titled: "Inconsistent/Unusual Brake Pedal Feel" and pertains to first gen 2003 onwards (WL calipers). This references the two piece updated Toyota anti-squeal shim kit. From what I gather some supplied anti-squeal shims from other manufacturers were one piece or were two piece where one plate was metal and the second plate was a noise dampening substance such as rubber, treated paper or other material. I know my PowerStop pads were made of metal over a paper type substance. I don't know if the factory stock original Toyota shim kit was one piece or two but this new kit was definitely two metal plates with one plate solid and one plate slotted. I can't say with certainty if it was the anti squeal shim kit or the replacement warranty caliper or the combination of the two that was the final solution as I immediately installed the right and left shims and the driver replacement caliper at the same time but the combination did correct the problem. At the time I did not change out to a replacement set of pads during initial testing so the pad were not the issue.

 

I think the information here is wrong. The shim is an anti squeal shim. Doesn't put the pad any closer to the rotors. Think about it. As the pad wears the piston extends maintaining the proper distance.

Brake shudder is is caused by out of round/warped drums or rotors. Bad brake performance is caused by inferior parts or bad adjustment. The mushy pedal described by the OP is either caused by air in the line or the rear brakes out of adjustment.

When I bought my Tundra in February of this year it had that same pedal feel. I put rotors and pads up front. I put new shoes and spring kits on both sides, cleaned and lubed the self adjusters and made sure they worked properly and adjusted the brake shoes. I also turned the also drums. I
adjusted the parking brake cable properly.

My pedal stays firm and no longer needs that little first pump. My truck stops firmly and smoothly.

 

I can only compare it to my 2019 crew cab and can say that the old truck brakes are comparable to the new truck under unladen conditions. I have not yet tried it pulling a heavy trailer but I now feel comfortable and competent in its ability to stop. The pedal is at least as firm as the 2019. I honestly think it was a combination of a partially sticking "new-rebuild" WL caliper from PowerStop and the updated anti-squeal shim kit. Someday I may disassemble it piece by piece to confirm the EXACT cause but after chasing this for months I'm a bit hesitant to do so just in case "some fu*king magic may have been involved. The fact that Toyota would issue the TSB entitled "Inconsistent/Unusual Brake Pedal Feel" for the 1st Gen years with the WL calipers says something. If I can find the TSB I will try to post again. As an attachment I have posted the actual Toyota shim kit invoice and part number I used and I did remove the original Power Stop provided shims when I installed the replacement Toyota shims. Remember it is a two piece kit for both sides (4 parts total). I hope this helps someone.

 

You are correct that it is an "anti-squeal" shim kit and shouldn't be moving the pad closer to the rotor. You might be correct about the rest as I felt the same way but even some "Pros"s gave up. I was not talking about shudder or inferior brake parts as I was using new PowerStop parts all around and had replaced and adjusted everything repeatedly (New rear brakes adjusted plenty, power bleed all corners plus LPV) as you suggested. I am just saying what worked for me after a very very long (and costly) trial and error. The only thing not changed was the master, power booster and ABS unit. Something did however change and changed in a dramatic way. It may have been something as simple as a slightly poor performing new replacement caliper from PowerStop that simply could not be seen with a naked eye. I have done many brakes on Toyotas over the years beginning with my 1979 SR5 4x. I have never been this thoroughly stumped over anything (along with some pros) and if I wasn't the original owner I would have believed someone had previously somehow altered and messed this system up - at least I knew the baseline. I'm ecstatic and wished I could provide a better explanation other than Fu*king Magic...

 

Here as an attachment is the Toyota TSB Bulletin

 

I bought one. I'll guinea pig it.

 

FWIW, if you order Toyota pads they come with the shims and paste, at least mine did. My truck wasn't suffering mushy brakes or squeal, but there was some low-speed shudder which went away with new OEM pads (and shims). When I got the truck the front pads were at 1mm, no shims, and very uneven pad wear.