2013 Rav4. Engine revs high when brakes are pushed in. Stopping ability is limited. I called a mobile mechanic and he agreed that the brake booster could be the issue. He also said the Master Cylindar was probably leaking as there wasn't any brake fluid in there (oops! I guess I need to be more diligent about checking those things).

Anyway, he said if brake fluid leaked into the booster, it means the booster would still need to be replaced. I'm wondering if that's accurate. Could this be a situation where the master cylinder is out and nothing more? BB part is over $500. Since it is out of fluid, I'm guessing the MC needs to be replaced anyway, and you have to remove it to get to the BB, so on a vehicle with a 170k miles, that will be replaced regardless. His service quote is no big deal ($240-ish). Tempted to just say go for it on all and have a new MC/BB installed.

Just wondering about the need for the booster. Any way to check the booster independently? Other thoughts?

I looked to see and the interweb says your Rav4 has a vacuum brake booster, which makes total sense with the symptoms you're experiencing. If the MC is leaking into the booster and ruined the diaphragm - each time you press the brakes you are introducing a vacuum leak - hence the engine revving. The lack of vac pressure is why braking is so hard.

Regardless of what caused the failure of the booster; it sounds like it's done. Without having seen it and based off what you have described - it sounds like he isn't leading you wrong and likely a booster and MC replacement is the way to go - if it were mine.

91AggieLawyer said:

---

2013 Rav4. Engine revs high when brakes are pushed in. Stopping ability is limited. I called a mobile mechanic and he agreed that the brake booster could be the issue. He also said the Master Cylindar was probably leaking as there wasn't any brake fluid in there (oops! I guess I need to be more diligent about checking those things).

Anyway, he said if brake fluid leaked into the booster, it means the booster would still need to be replaced. I'm wondering if that's accurate. Could this be a situation where the master cylinder is out and nothing more? BB part is over $500. Since it is out of fluid, I'm guessing the MC needs to be replaced anyway, and you have to remove it to get to the BB, so on a vehicle with a 170k miles, that will be replaced regardless. His service quote is no big deal ($240-ish). Tempted to just say go for it on all and have a new MC/BB installed.

Just wondering about the need for the booster. Any way to check the booster independently? Other thoughts?

---

Says who?

Google reveals that part is from less than $100 to more, lol.

I wouldn't pay more than $225 for the brake booster for a 2013 damn-near anything. Look into it. Save some quid.

JamesPShelley said:

---

91AggieLawyer said:

---

2013 Rav4. Engine revs high when brakes are pushed in. Stopping ability is limited. I called a mobile mechanic and he agreed that the brake booster could be the issue. He also said the Master Cylindar was probably leaking as there wasn't any brake fluid in there (oops! I guess I need to be more diligent about checking those things).

Anyway, he said if brake fluid leaked into the booster, it means the booster would still need to be replaced. I'm wondering if that's accurate. Could this be a situation where the master cylinder is out and nothing more? BB part is over $500. Since it is out of fluid, I'm guessing the MC needs to be replaced anyway, and you have to remove it to get to the BB, so on a vehicle with a 170k miles, that will be replaced regardless. His service quote is no big deal ($240-ish). Tempted to just say go for it on all and have a new MC/BB installed.

Just wondering about the need for the booster. Any way to check the booster independently? Other thoughts?

---

Says who?

Google reveals that part is from less than $100 to more, lol.

I wouldn't pay more than $225 for the brake booster for a 2013 damn-near anything. Look into it. Save some quid.

---

https://autoparts.toyotaofirving.com/products/product/booster-assy-brake-446100r060

If I don't need the total assembly, let me know what I need. I don't want a remanufactured part. Even though it is 2013, I'm planning on keeping this long term.

I'd go reman aftermarket or new aftermarket if you just have to have new. This is not hard to replace. That said, make damn sure it's diagnosed. I have a LOT of high mileage vehicles, one with 450k+ miles and it has never had brake boosters or MC replaced. The only vehicle I have ever needed one is my 77 F250 and that was because it sat unused in my buddy's driveway for 17 years before I bought it.

My brake booster is acting up on my Nissan, and I'm about to change it out. They run about $100. It can be tedious as sometimes the bolts are hard to reach in many vehicle models, but often you can shimmy it out without having to fully detach the master and having to re-bleed the brakes.

$500 might have been parts and labor?

I had a master cylinder go out in a 2007 chevrolet silverado around 2012. Less than 100k miles. Backing out of my driveway one morning and the brake pedal went straight to the floor as I tried to stop and shift from reverse to drive. Mechanical things brake sometimes.