Brake pedal creep

I test drove a new 18 OR and I also felt the brake travel was out off the ordinary... I ended up buying a used 17 TRD Pro and noticed a significant difference. The 18 didn’t feel right, definetly felt unsafe and wouldn’t imagine being caught in a emergency braking situation. Good luck hope they figure out whatever is going on.

 

The brakes suck soo bad in this truck and the dealer still cant fix my issue with feeling the truck bang with each downshift. This truck has 15,000 miles and i noticed the brake master cylinder is leaking.

 

My service advisor told me they get a lot of complaints about the 2 to 1 downshift thump (and no fix available). I had it in my '18 pretty bad. Felt like getting gently rear ended.

Subbed for OP outcome.

 

I had this aswell. Something that helped it out a lot was greasing my driveshafts. 60k on the truck and the dealer that serviced it never greased them

 

What type of grease is recommended

 

Whatever is in your grease gun should be ok, you will probably only have Zerks on the Front Driveshaft on your 2017.

 

Except for frame issues.
Crap, looking at 2nd gen forum on fairly new trucks right now I see new engine needed, bad throttle bodies, cab leaks, rust under seats, rough idle, check engine lights, high tranny temps, no power to fuel pump, etc etc etc.
My head is spinning.
All on the illustrious......... 2nd gen. Go figure.

 

2nd gens are having their issues that's for sure

 

Glad I never had any issues like that in my 2nd Gens, pretty much was limited to a few lightbulbs and a door rattle.

 

Had same problem on my 2016, brake master was leaking into booster. When truck was off pedal would sink to the floor. Dealer replaced after finding the problem. Now when truck is off brake pedal is solid. But the weird thing is that before and after replacement when truck is running the pedal is still sinking to the floor when i hold it down. I have bled it twice and it gets better so i'm going to wait a few weeks and bleed again.

 

I had a similar problem with my own Taco, but it was self-inflicted: loose lug nuts on front wheel. I've no idea how a loose wheel would affect brakes, but it did. Pedal was spongy and required pumping to (temporarily) get it to a normal state.

Jacked the truck up to remove the wheel and look at the brakes, noticed the loose wheel, said a quick thank-you to sky Gandalf for keeping me alive through such stupidity, tightened it up, problem went away.

 

OP here. Gentlemen, thanks for your input.

Brake pedal still heading for the floorboard.

The truck went to a dealer, Toyota Corp. Customer Service approved. Service manager checked the pedal, immediately said "That doesn't feel right", left the truck for a couple of days. Got a call, truck was evaluated against another on the lot. Svc. Mgr. said the other truck, a new TRD Sport did the same. I compared the two, pedal on the new truck sank about 3/4" & then firmed up.

Engaged the Svc. Mgr. in conversation & learned a few things about the Toyota warranty program. Svc. Mgr. stated the Sport & SR series booster systems were vacuum operated, the OR was electric. As Toyota allowed payment under warranty only for an effective repair and as they couldn't identify a specific fault, they would not be compensated for "throwing parts at it" until the cause was addressed. Caught in a ringer, Svc. Mgr. reported to Toyota, "They all do it".

Referred back to Toyota case manager. Asked for a second opinion, Case Mgr. agreed. With some reluctance, second dealership's Svc. Mgr. (also senior tech) agreed there might be something going on that wasn't entirely copacetic. A corp. technician is scheduled to inspect the truck sometime in the near future, "In two to four weeks".

TLDR: Brake pedal sinks towards the floor under moderate pressure, it's also evident during a long stop. Although two Svc. Mgrs. admit something isn't right, neither is eager to touch the truck because they'll not be compensated for parts/labor for an ineffective fix. It's now being kicked back to Toyota Corp.

My considered impression is the master cylinder is good but the booster is bleeding pressure. It's not the sort of thing that gets better on it's own.

Small progress, just glad it isn't (yet) a life threatening situation.

 

Does the brake fluid reservoir remain full? If it does it sounds like you may have an air leak into the system. Bleeding it might help as a temporary fix to push any air that is entering the system, but the issue will likely return. It could be time consuming to source an external air leak into the fluid system, probably a good part of their reluctance to start working on it.

 

Air in the lines or master. Or a leak in the system somewhere caliper or wheel cylinder . Sounds like a your truck issue . Not normal.

 

I had zero issues with my second or third gen except a recall on the 3rd for CPS with no noticable faults . The 81 sr5 4x4 had some issues though. Mostly from old age and sinking it in mud and driving through higher than floorboard water lol.

 

Hi, Elduder: Seems you know your way around brakes. Thanks for your knowledgeable comments.

M. C. reservoir level stays constant. When truck is off, pedal is rock solid. Turn truck on & exert modest pressure (lift heel from floorboard, maybe push a little bit harder) & pedal starts migrating south.

No confirmation but characteristics point to the brake booster bleeding pressure as if the diaphragm tends to relax under pressure, perhaps a slight leak at a gasket, valve or seal. Brakes actuate nicely, steady on the pedal for a while & whoopsie, there she goes. Hydraulics (M. C. piston seal) a possibility but not MY prime suspect since it maintains a firm pedal when turned off. Greasemonkey67 suggests bleeding the brakes (thanks to Gm67 too), that's what current warranties are for.

Rebuilt a couple of M. C.'s in the past (EZ-PZ) & had a (Ford F-250) brake line blow once so I do know where the hand brake is. However, somewhat disappointed to have these concerns with a 2018 Toyota.

& yeah, techs/svc mgrs admit something going on but reluctant to attempt a correction. At the local level looks like it's all about the $$$. Toyota Customer Svc. continues following up.

(Edit) "A your truck issue". Yes it is that.

 

If you still have warranty won’t they just take care of it?

 

Sounds like you have a solid grasp on troubleshooting it. Once the truck is turned on the booster starts, so your suspicions seem warranted. The only thing I can recommend is pressuring them on the "safety concerns/risk warranted by your brakes working improperly". Saying something along those lines should get you a loaner and get your truck in the shop. I feel you on the new truck having issues thing, my last Taco was enough of a problem that the dealer bought it back. I would let them do the work and troubleshooting, it's unlikely anything you suggest to them will make any difference. They'll listen but they will still have to go through their troubleshooting process to explain to their superiors why they did what they did, in the event that it may need to come in again for more work.

 

TL; DR huh.
The dealer is saying it normal. At least the first one. Not everything is just accepted for warranty because you say there is a problem. Dealer goes on the assumption that all buyers are stupid and dont know as much as them. So they claim normal and you have to prove them wrong.

 

I'd like to hear the outcome. The only booster issues I've encountered where excessive pressure . Dragging of the brakes and excessive heating of disks and discoloration of rims and rotors due to too much pressure. Drums dont seem to discolor or warp as bad .Too bad you can never get a straight answer from a dealer .