2014 with Magnuson SC and brake nightmare

I’ve been to dealership one time. They voided my remaining year of warranty because my trans fluid “didn’t appear to be of oem type”. I have redline in it. I despise dealerships especially Toyota and with the sc I just envision them telling me I need new abs and booster (as that’s what the codes show) even though it’s a brand new oem booster I put on it (I’m sure they will say well an asci Toyota mech didn’t put it on yada). That part was 900$. All that said I may still take it in at some point just out of curiosity but honestly I’m convinced it does more harm than good (typically).

 

I am going to try a few things before I take it in.

pull abs fuses = retest.
Hook booster vacuum to different cars vac source. = retest
Possibly install an electric vac pump or tank.

there’s not much else I can think of short of putting another used abs pump on it or god forbid a new one.

 

How many miles do you have on your blower? What was the mileage when you installed it?
Thanks

 

I had similar issue on my SC 2010. Chased brake issues for years. It was inconsistent in braking and had a soft pedal. I’m pretty sure the issue was in the vacuum, but every time I took it somewhere the mechanic would say it’s fine. I changed everything out too except abs module, but I had a device to activate it to bleed it. I finally traded it in cause the trans was also going out for the second time. I think you are on track regarding the vacuum issue.

 

Read through this entire thread. I don't have a SC'r so have nothing to add. Really hoping you can find a resolution @jolobeans . Keep us posted on what happens whenever you run the additional tests or what the stealership finds/doesn't find. The saga must continue!

 

Yea thing has been a SOB. So truck had 45k when I installed maybe. Drove it about 5k miles before all hell broke loose pulling out of driveway one morning. Abs activating, pedal hard. Codes on booster and abs “skid control” . Anyway. Off to the races replacing crap from there on. For weeks. It’s way better now and I honestly think maybe it was doing this before but I never thought to sit there and pump the pedal few times. Or maybe not. I do know I drove it all the way to DC from NC few days before this thing failed. Did fine but maybe something heated up and started leak?! I have no idea. Thought I read someone had sc w vac leak that ended up being sc bolts where it mounts on top. Torqued em down and good to go. I haven’t tried that but I know I put em in right first time and mechanic swears a smoke test would uncover a vac leak there

 

Is the brake booster getting its vacuum source from the correct spot on engine?

 

Side note. This is by far the lowest mileage and newest vehicle I’ve ever bought and also by far the biggest pain in ass at this point. (And I’ve had 20yr old Ducati. 20yr old Buick’s. Old Honda’s and Subaru’s. ). Leaves a bad taste in mouth I tell ya

 

Why not just put a vacuum canister on it and give it a try ???
Its about the cheapest thing you can do and the most likely solution to your problem.

 

Yea booster comes right up from middle Port on sc. there’s 3 where all the vacuum is supplied. Left one is where pcv enters back in from just below. Right one is to the vac solenoid. I think.

 

Yea good idea. Honestly I’ve been busy as hell trying to get house painted but will look at vac canister if nothing else works. I don’t have any experience or even know what to get for that. I guess they have electric ones too. Read up on them for a little while a few weeks ago

 

Pulled both the abs fuses. No change. Also pedal doesn’t sink unles the vacuum is depleting. So use pedal 1x.. no sink. Use it 5tines real fast sinks quite a bit slowly (sort of as the vacuum comes back). Then use pedal 1x no sinking again. This HAS to be a vacuum issue but I don’t know why. If I have a leak I need to fix the root issue not just compensate the booster to fix just the pain in ass brake system.

 

While in park, revving the motor up to higher RPM, do you still get the fade? Seems like this would create more vacuum for the booster. Then you would know for sure if you are lacking vacuum.

 

Hi. No typically with sc or booster when you rev engine it produces boost which is opposite of vacuum. This is the reason I’m suspecting a vac issue as it only pulls vacuum after letting off throttle at idle (albeit maybe not quite enough). I’ve tested that with a vac gauge and it appears to be within spec at idle... but just sitting an revving doesn’t change things if I’m pumping pedal from a stop.

 

Have you pulled vacuum hose feeding booster and checked it for cracks or blockages?

 

Yea. First thing was done. Check valve is good and have tried 3 different boosters at this point all with different check valves. The hose came brand new from Magnuson. I can’t remember where the old one is though. But I believe they were of the same diameter. Chance that’s different I suppose. In any event I pulled engine vac reading at end of it where it plugs into booster and seeing 17in psi or so. What I can’t find is what the spec is for tundra (or even better for a tundra w a TVs1950 blower.). Generally 17 is within spec for a decent engine though from what I believe. Shop said they were seeing 16 but they didn’t know the vac spec either. What I do know is that is at idle and when you give it gas it will spike to needle to 0+ under boost then settle back to vac reading around 17 to 20 at idle. If anyone out there knows what a stock tundra pulls at idle for vac would be great to hear. At this point I believe dealer visit is in order but I feel I’ll be wasting $ there. Otherwise trying a vac booster or extra tank but I need to research what to do there unless anyone has any recommendations.

 

I do think when running along at 50mph and off throttle it probably pulls better vacuum due to engine breaking but I’m not sure of that. That may be why I don’t seem to have issue unless I’m slowly rolling or just pumping it coming up to a light. Slamming on in hwy running along at 70 after not hitting pedal for 1min or more brakes work flawless

 

Ok, just a quick observation as I think all of the "hose clamp/worm screw clamps" are just securing heat shield type material, but are any of them being used to secure a fitting btwn hose/inlet or outlet vs the tension type clamp? I know we used one vs the correct tension type clamp on a tractor one time for a temporary connection as we didnt have the correct size tension clamp on hand and even though we cranked down the "worm screw clamp" as much as possible it would still leak under load. Just spit-balling to see if wrong type of clamp was used somewhere and me be failing to seal properly.

 

Yea. Just the one in the pic from the pcv where it goes back into sc. that shouldn’t even be seeing vacuum at idle. Just under boost it will force some air out and back into manifold. I guess. Anyway that’s where I originally had a long run to a catch can and then back in where the worm clamp is but that was the first thing I took off just to rule out that long run of hose and whatnot. Had it on for 10k miles prior to the sc tho with no issues.

 

I think IF it’s a vac leak, it’d be where sc meets the top of engine. Where injectors and gaskets all are. Some of those bolts are near impossible to get torque wrench on. Again shop guy swears smoke test would show a leak there if it were there or anywhere for that matters

 

That other worm clamp at lower left are for the coolant.

 

Alright. I’m gonna order a vac canister tonight. Although I gotta say if it’s a vac issue I’m more concerned w WHY I have a vac issue. Not really the issue at this point as I can drive it and knowingly not cause it fk up just by not pumping brakes. More worried something is wrong and engine maybe running off from it although I haven’t really noticed anything that I can say.

 

Just a stab in the dark, have you talked to Magnuson? Maybe something with the SC gate/bypass not closing completely.

 

Thanks @ZPMAN. That issue seems much more common across these tundras. Being this is a used abs pump w 50k miles I am not sure what could be wrong w it. But mine only had 46k miles. Anyway issue doesn’t seem to be same as my abs sorta activates at will so I’ve exercised it plenty of times. Also I tried all the slam it on gravel stuff. Hell even took to outer banks and raced it sand. His doesn’t indicate rock hard pedal with is sorta central to my problem. Also mine works excellent when driving fast (but not when slow). I appreciate the comment tho as I am at a loss w this thing. Going to bank on vacuum leak or low vacuum anyway for now and see there this goes

 

Ordered this last night.

$123 CVR VPR700 Billet Aluminum Power Brake Vacuum Reservoir w/Check Valve & Gauge

https://www.amazon.com/CVR-VPR700-Billet-Aluminum-Reservoir/dp/B071J1JW7N/ref=mp_s_a_1_3?dchild=1&keywords=vacuum+canister+booster+with+gauge&qid=1601825516&sr=8-3

I don’t know if it’s the best one for my application but it looked trick and has a vac gauge built in. ive been meaning to get an AFR gauge as well anyway w one built in but not gotten around to that.

 

Haven’t spoken to Magnuson. Honestly that’s a great idea. I thought about it but forgot. Sorta got crappy service from the guys that did the tune there but maybe I need to be contacting someone else.

 

I think the issue is between the manifold and the booster. Maybe the check valve is not flowing enough to recharge the brake booster. Make sure you have the correct type. That vacuum line is wrapped, probably hard to tell if it's collapsing or not.

It is NOT a leaking S/C bypass valve. It stays open unless the engine is under boost. It closes in order to retain the pressure difference between before and after the supercharger. I am no expert, but I did own a supercharged GTO for 10 years.

I would ask around on other forums where people commonly supercharge their vehicles. Maybe a corvette or camaro site.

Also, on the LS2 it had 21-22 vacuum at idle. However, that's a different engine.

 

I’ve tried a couple of check valves. 3 actually as I had a new one on each booster I tried. The latest one that’s in it now is a new OEM one. Can blow through it one direction. The hose is brand new. I don’t know for sure if it’s exactly like the old one though. Something tells me it’s wider but it fits tight on the same oem check valve. Appears to be standard vacuum rated line. (Not coolant line or heater hose I mean). I ordered some 15/32 gates vacuum line with the vacuum tank I ordered so will see how it compares.

 

I’d be curious to see if just the Gates hose makes any difference.

 

So I attached the canister and not sure I’m seeing any difference. Under 15mph or so on a roll can still get it to throw codes if I normally press brake for about 1sec on .5 off 1sec on .5 off 1sec on... then about there (if you press through the hard pedal that’s developed) it throws codes and abs will activate and grind. Rolling 30 or 40+mph tho this doesn’t happen I noticed. Def something with vacuum keeping up it seems like. Anyway hose is identical the the 11/32 gates hose and vac at idle on canister reading about -21.5in. Returning this as not seeing the benefit here (or where the hell to even mount it). Maybe a full on electric vac pump would change it. Or maybe I’ll just say to hell w this crap and let dealer look at. I am 95% sure that will be a waste though and based on past experience chance of them screwing something else up is my biggest worry.