Hi everyone! Recently I've come to notice a major issue when breaking! Every time I come to a stop sign, and press on the breaks, my car idle become erratic and almost feels like the car is misfiring, occasionally would even stall the car, the only way I've combated this issue is by slowing the car down by lightly pressing on the breaks and come to a roll. I've come to find a huge leak coming out of the brake booster vacuum line (Part 44773-24040) I've tried hunting down the OEM part but it seems as if the part is mostly discontinued, so I've turned to look for an aftermarket solution. Does anyone have the size of the hose that is needed to replace this part?

 

Indeed the OEM pre-made brake booster vacuum hoses are discontinued. I also discovered this in 2018 and so I took some of my old hose to a common auto parts store (probably Autozone) and I got a couple feet of whatever inner-diameter *fuel grade* aftermarket hose best matched it. I don't recall the exact size that I used but this worked perfectly for me. I just cut the aftermarket hose to the lengths I needed.

I also bought all new OEM clamps to be sure that the old ones presented no sealing issues. In the Toyota EPC these are 90467-16017. In my own build thread notes I think I may have used 96135-41400 instead but I am not sure.

This post in my thread shows a picture of the generic aftermarket fuel-grade hose that I used and cut to length on the car. Note that the engine pictured is a GTE, not GE engine but other than that and the hose routing (and I hadn't relocated the in-line filter back to the firewall mount yet in that picture) there is no difference in what you must do. Just cut the new aftermarket hose to the lengths that you'll need.

I've had no issues with it. Just make sure that the inner-diameter matches your old worn out OEM hose's inner-diameter. It MUST be a "fuel grade" style hose because it's just built from much stronger stuff than common vacuum/washer hose.

https://www.clublexus.com/forums/bui...l#post10241304

 

Hope it’s just the vacuum line.

Kahn, u always helping out.

My ‘99 sc300 had its booster go bad, ripped diaphragm. Got an aftermarket booster and was pretty straightforward to install…if you don’t mind laying upside down for hours under your brake pedal trying to figure out how to reach booster bolts.

 

Hopefully it's just that in his case, yes. Eventually power brake boosters will go bad from a ripped diaphragm but from brand new OEM it should take a couple of decades or more. They are annoying to install, yes.

Interesting side note: For now or until just recently Toyota was having brand new OEM boosters made for the Supra MKIV chassis through their GR Heritage Parts division. I think one of those booster designs will fit and work in our SC300's. Hefty price tag for them however if still available.