Ninjaneer11

I had first-hand experience of chain tensioner parts finding their way to the oil pan. Found this in my L20b when I took it apart to rebuild a couple years ago. Not certain if that's what you are looking at, but yours look much smaller and hopefully didn't do as much damage on their journey between the front cover and oil pan if so.

I think I have two issues going on here. I replaced the master cylinder last night and the pedal stays firm now, so I believe the old one was bad. I still get the air noise when pressing the pedal though. I replaced the booster hose to be double sure that wasn't the issue. This time I do feel some air coming out around where the hose connects to the booster when the pedal is pressed. It's in a specific spot that I might have missed before. I believe the issue is on or around the push-on fitting on the booster. The new hose fits very snug and has a clamp on it, so I'm confident it's not the hose. I can't see or feel anything well enough to determine exactly where the leak is though. I'm going to have to take the booster off the car to get a better look. I checked the FSM and It doesn't look like there are any seals or gaskets around that fitting that could be replaced even if rebuilt though. Does anyone know if this piece is press fit in or how it might need 'resealed'.

Thanks for the info Seppi72! I have a zx master cylinder which works well with the bigger brakes. I ordered a replacement that I will replace this weekend. If that doesn't solve my issue I'll be sending off the booster to get rebuilt.

Thanks Zed Head. The calipers are mounted with the bleed screws up. The setup I have makes it impossible to mount them on the wrong side since the hardline from the caliper is fixed to the strut tube. I'll try bleeding the MC again tonight and if that doesn't work I'll start by just replacing the MC since they are readily available. If that doesn't fix it, I'll do it all again after getting the booster rebuilt. I'm going to be so good at bleeding brakes when this is done.

Good to know. I can't feel any air movement. I checked around the booster, MC, and vacuum hose. I used a piece of empty tubing up to my ear to see if I could pinpoint where the sound was coming from too. It seems loudest inside the booster, under the MC.

I just tried this. No change to rpm no matter what I do to the brake petal. This was in the garage starting it with the choke engaged, not sure if that matters or not.

I just had my front brake rotors resurfaced due to some pulsating while braking. Disassembly requires disconnecting the hydraulic line from each caliper on my setup (older wilwood arizona z car kit). I put everything back together with fresh pads and flat rotors this weekend and started bleeding the lines, but I hear an air "breathing" noise when pumping the petal. Here is a video of me pumping the brakes https://imgur.com/a/w5kBNBj. Please excuse my fumbling with the pedals, it's hard to video and pump the brakes while standing on one leg. The brake petal also won't stay firm. It will firm up when you pump it, but get soft after a bit of doing nothing. The petal was firm and worked great before this rotor project. I have: "bench" bleed the master (on the car). gravity bleed the lines. used a one-man vacuum bleeder. had my wife help me do the ol 2 person bleeding procedure on all 4 corners and I still get this noise. This isn't my first time bleeding brakes and have done them successfully on this car before. Other things I checked/tried: It's not leaking fluid anywhere. There are no bubbles in the lines when I bleed them. I checked and tightened the vacuum line to the booster. Replaced the check valve with a new one I had in my parts stash with no luck. Has anyone seen this before? I'm assuming it's a bad booster or master, but was hoping for some advise before I start ordering parts. Could draining the master have created a leak due to old seals or something? It looks like a booster would have to be rebuilt too since they are not available. I have a 7" early 240 style booster with a 15/16 MC. It's driving season where I live and am hoping to get back on the road asap!

Yeah, the t stat bolts were correct. I don't have much history on the truck, but I know whoever set the timing didn't do it by the book. L20B motors are supposed to be set at the #2 cam gear mark initially and this was set at #1.

Hey Guys, long time lurker, first time posting. I am going through a rebuild on the L20B out of my 620 and had a similar problem. I've been scratching my head as to how the guide would break like it did and this had shed some light on it. A few dings in the oil pan, scratches on the front cover, and almost worn through oil jet were the result. I'm surprised it didn't do more damage. I appreciate the knowledge that gets shared here.