2014 with Magnuson SC and brake nightmare

Hi all. Opened this account as I am at wits end. Long story short, installed Magnuson SC on truck about 6mos ago, no issues seen. Drove it about 5k miles. It’s on the base tune still. Anyway fast forward 5 months or so since install. I pull out of driveway one morning and get CEL. Brake pedal hard and feels like booster gone. Basically I’ve replaced whole brake system now. Codes and tech stream all pointed to brake booster OR skid computer/abs pump. So after going round and round I now have a new OEM master cylinder, oem brake booster, (new stainless limes and rotors and pads but most of that was needed anyway and not the issue). Anyway codes are gone for good but issues still remains IF I pump brake pedal 3 times real fast at idle or while rolling slowly. Pedal will go hard, feels like no vac boost. Let it idle 5 sec more or so and pedal feels fine again. (For one or 2 pumps). Check valve on booster is good (as was before booster replaced). Ive checked vacuum at idle and it’s about 17 or so. Seems to be in spec. PVC is fine. I had a catch can on for couple years but pulled that off just to rule it out. Vac lines all good so far as I can tell. Lots are new since sc install but otherwise truck only has 48k on it and is mint. Truck drives perfect otherwise now ( as long as you don’t pump the brakes 4 or 5 times rolling to a light quickly). I really don’t know if it did this since SC install as I don’t believe I ever pumped the pedal like that. I don’t think it used to sink tho. Pedal also sloooowwwly will sink down at a light w foot on it. I’ve been working on cars for 20yrs and never had a brake issue like this. I’ve bled the lines as well about 10 times and also used tech stream to abs bleed. Gave up and paid a shop to do it and they also found no air. They were stumped. I asked em to check for vac leaks and they smoke tested it and swear no leaks. I am thinking it’s a vac issue and maybe something loosened up after 5k on supercharger causing slight leak. Maybe the sc itself on manifold.... it’s at least driveable now but still pisses me off. I believe it as a booster issue initially but still something else going on at this point OR the sc just changed vac enough but I never noticed this after install. I can’t tell now. Out of ideas!

 

I am thinking about pulling my Acura up next to it and running the vacuum line from its booster over to the tundras and plugging it’s other end. (Using Acura’s engine vac to supply the tundras booster). Just don’t have the hose yet to do it. That or looking into installing an electric vacuum pump like the old school muscle car guys would have to do to get power brakes after boosting engine or crazy cams installed. Really don’t wanna go there though (yet) as it is relatively unnoticeable unless I fk with the pedal and make it happen. Does anyone have any ideas or know if their 2014 with or without sc does this crap when they pump pedal 4 or 5 times at idle or while stopped?!

 

Forgot to mention also put another abs pump on it (well 2 different used ones anyway). No change. So used abs pump and new oem mc and booster.

 

in my experience, a sinking pedal points to a bad master cylinder. if it's leaking brake fluid into the booster it can mess up the vac assist, too.
Realizing that you have already replaced those items, I would still look at them.

 

Have you try swapping out the ABS control module?

 

Hi yeap I put a used abs pump on it (2 of them in fact. Also it’s a brand new booster and brand new MC on it now). It’s doing the exact same thing it did with my original abs pump tho. I don’t think it’s the hydraulics because brakes work perfect (unless you pump them 4 or 5 times rapidly. Pedal gets harder and harder and you lose brake assist. That’s when you can feel it slowly sink and the sinking coincides with the brakes “regaining” the power assist/booster vaccum it seems like. So soon after that (maybe 5 sec brakes work perfect again). That’s all while slowly rolling or sitting still. Otherwise can slam on brakes when driving and pedal feels great and will lock them up even if you want . I don’t get it. I’m convinced it’s a vacuum issue but no idea where it came from. I have to assume something to do w the supercharger and I just never noticed it until whatever failed w the brakes. Evidently that’s fixed and no longer getting codes at least and brakes completely driveable. Unless I sit there and pump them ... I don’t get it

 

Something is askew with your ABS pump I feel...tho the codes are gone, or seems the bleeding of the brakes might need to be addressed again...I thought the ABS self bleeds but sometimes there's a sequence one must do to mitigate these pedal feel issues...

Edit: Can you make sure your grounds are solid and are you running a catch can with the SC'r? I'm trying to figure out in my head what variables might be presenting themselves as possible culprits...I have the same setup for the most part but my brakes and pedal feel seems fine...tho, I haven't given it the rapid pulse method yet...

 

Yea I thought so too. I have bled them about 20times however as well. Also did the whole tech stream abs bleed stuff (many times). Also took to a reliable shop after all this and he bled them with his scanner that does abs bleed = no air). I asked him to check for vac leaks and he smoke tested it all and swears no leaks. I thought maybe sc had a leak around manifold but guess not. This is a bitch. I am gonna book a vac line to booster from another car and see what it does at idle if I pump the brakes and check pedal. I don’t know what else to do. Also abs pump is only part that’s not new OEM. Mine only has 46k on it and this used one on currently is about 50k w a 6mos warranty.

 

My fingers are crossed for you to find a solution! What a PITA! I couldn't imagine the SR'r is causing issues with the pump but it IS forcing more air through the engine and it's all indirectly connected in some fashion. Hmmm, I've heard sometimes when upgrading to SS brake lines one can feel more pedal firmness but this seems too much for this to be a consideration...I will have to think on this a bit...hang in there and it seems to always be the "simple" stuff at times...my fingers are crossed that it is indeed a simple "fix!"

 

Did you set the gap between the booster and master cylinder? I highly highly doubt this is the issue but you never know. And where you describe rapid pumping it sounds like it could be something worthwhile to look into. Usually this is more an issue with go-carts and non vacuum braking systems

 

Try putting an aux vacuum canister inline with the brake booster.
It sounds to me like you have a lack of vacuum going to the booster.
Superchargers can cause problems like this.

Where are you pulling vacuum from ? before or after the rotors ?

 

@Hulk I did replace the lines just for hell of it but was acting like this prior to doing that. Goodridge stainless.

@dragon art. Yea I was thinking trying that but far as I can tell no one has had issue like this online due to sc. the check valves supposed to be compensating for that and check valve is good. It does act like vac is there tho until depleted quickly and then takes a bit to build back up. That’s why I think vacuum. The light sinking seems like it’s as vacuum comes back and slowly pulling more pressure on mc (if that makes sense). At engine speed tho when normally using brakes no issues. Vacuum seems to be fine at 17in lbs at idle. Reviving it drops to 0 but that’s normal under boost as I understand it. Soon as you take off gas goes back to vacuum. I dunno.... that’s why adding reserve vac tank seems like right path... I just don’t know why mine would be doing it. It’s pulling vac from right in front of turbine after throttle body. Sc has 3 ports on it there. One to booster and one is where pcv loops up and right back into sc manifold.


@Ditto. Yea I tried to set it. It’s about 2mm from the top of mc piston while running based on my measuring. Maybe 21mm I wanna say from bottom of piston.lThen i could feel dragging in wheel caliper so set it back 1 thread. Then other way one turn. Round and round I’ve been w this . 2 different boosters before getting a oem one. I believe it’s set just right.

 

At engine speed rolling it WILL do same tho but you have to pump them while coasting up to a stop light. So basically at idle or around same pressure 17 to 19in or so per my gauge at idle.

 

Ohh forgot to ask guys can anyone take a look at a factory booster pushrod and count the threads on it to the nut? I think I’m at 5.5 or so. Maybe 6. I can’t see how that would make that much of a difference unless it’s too tight. Mines too loose if anything. Thanks for the replies!!

 

So if I really pump them and give it some force one pedal goes hard on a slow roll up to light the abs will kick in and throw codes. Usually same ones. (Stroke sensor 1301 and or active booster solenoid.). Same ones I had before but were always on until swapping all this shit. It’s the ones on booster and all the techstream docs point to booster or abs pump always.

 

Pedal does feel spongy this it works otherwise. Can hear the whoosh air when pushing it. Maybe is air but I’ve been on the bleeding for hours/days on this and half a gallon of fluid. Also shop did it. We didn’t use the mc force bleed thing tho that pushing fluid through. I dunno

 

I didn't read the entire thread but your pedal feel caught my attention. I've experienced this hard pedal feel off road when I've confused the ABS system. Basically braking hard in certain conditions the pedal goes rock hard and brakes are nonexistent. Anyhow, I believe your issue is in the ABS system, not necessarily the pump. You can test this easily by pulling the ABS fuse and trying the brakes.

 

Great idea! Yea it’s either pedal going too far or vacuum/hydraulics messed up so when pedal goes hard or too far the sensors on booster trip and tells abs pump to go whacky and starts engaging. Still think root cause is vacuum or something but the end result and codes are from abs kicking on and it outta whack . I will try that need to go find abs fuse.

 

The hard pedal feels more like no power assist but if yo really get on it after that point it gets stroke sensor or something out of range. I think it’s supposed to be .50 to 5v or something like that or it throws stroke sensor code. Most of that checks out under normal testing w scanner. (Usually)

 

Do these bleed with the abs pump like Tacomas ? I wasted a gallon of brake fluid trying to bleed them like normal before I found some obscure post that showed to turn the key to on and open the bleeder and the abs pump will pump out the air. It worked.

You could ask Matt@ovTunes their shop R&D for tuning platform truck is a Harrop 2650 Eaton Supercharged Tundra i believe.

 

Not familiar with the Tacoma. But good scanners or the techstream oem software has a bleed procedure where it activates the pump to bleed air out. My Acura rl has actual bleeder on the abs pump though. Nothing I have done with the bleeding has improved anything. It doesn’t seem like an air issue.

I checked and there’s 2 fuses evidently. An 40 and 50amp in spots 38 and 39 engine box. I need to go confirm but I’m guessing pull them both and see how she goes... will report back tomorrow.

 

I thought ov tubes wasn’t doing tuning anymore? I tried to get in touch with him 6mos ago and he said they weren’t supporting tunes anymore. I did speak to a shop in nc that deals with other turbo and sc tunes and he said he’s never heard of sc causing brake issues. This has been a nightmare honestly. And I’ve been working on cars for 25yrs. I’ve cussed Toyota more times over this than can be counted.

 

ov tunes made tuner software so any tuner shop can custom tune it. It comes with an option for OV tunes developed base tunes. But they planned to stop personalizing tunes from Data logging.

 

@PeakIT wow that sounds decent. I have the Maggie base tune in it and I know in tow haul mode it’s all whacked out if you get on it. Never shifts and just bounces off rev limiter in 2nd or 3rd. Seems like the overall shifting could be better in drive mode as well. Otherwise just hope it’s at least safe at this point was my main concern. I’d love to know a shop that uses the ov sw or tune in NC or somewhere that is good w the tundras and Maggie/hp tunes at least.

 

If you pump it like you stated, that is normal. It has to "replenish" the vacuum.
With the pedal sinking that is a bad master OR it could be a leak somewhere in the system.

 

That’s interesting as I haven’t had that issue on any other car ever I’ve owned. Can pump brake pedal till cows come home. Always travels same distance and applies brakes w same force. I haven’t ruled out the leak... but damn, almost everything has been swapped. Internal leak in abs pump... maybe. But no change between my original pump and 2 different used ones? Doesn’t seem likely.... thanks for the info tho. If can be confirmed that any tundra pedal goes hard after few lumps and loses power assist that would be a gem... as can focus on pedal sink

 

It can hold only so much volume of vacuum, which is usually 3-5 pumps of the brakes, now if the truck is running you might get 7-10 before the pedal goes hard.

Also depending on your line to the booster, if it was replaced with fuel line, it could be sucking shut.

 

Yeap that’s why I’m thinking maybe what I’m seeing now is was due to supercharger install and I never noticed it before. Until having issues. It did get new lines for the Magnuson kit which changed the hoses to booster. Seems like right stuff tho. Def not sucking closed. I can’t see how this is normal tho. I can hit it hard once it loses vac boost and get abs to trip

 

Also why I think a electric vac pump could solve this. If never loses power / vac boost it would be perfect. If that’s what they do. Why would no one else be complaining about this it it’s normal though? I can’t find any online

 

My ‘14 is supercharged and none of this has ever happened. I have skimmed this thread and I still cant hardly imagine how its tied to the SC?

No doubt you have an issue though. Symptoms seem to be classic air in the system or you have a bad master cyl or possibly a bad brake booster. Given you have swapped them all out, I suppose its possible one of those new part could be bad but not likely.

Ever take it to a Toyota dealer or talk to a tech to see if they have seen an obscure issue on these trucks?