arsonist63086

hi been a long time since I posted on this forum since I lost my 1st gen (85) and my 0 gen (77) got t-boned (fixing it ). so my question for today is about my 90 max se with abs system . just recently (last week) my brake pedal has been sinking at random times feeling as if I have a leak in the system I pump twice and it's fine again hard and firm again (no pun lol) till random moment strikes again and it sinks low (but still stopes). I recently changed the master cylinder about year ago new rotors up front and pads are still good with about half meat on them (been a year since I changed the pads with duralast gold pads(same as c-max) all around, excellent pads&#128077. no visible leaks anywhere , not the 4 corners, master cylinder or abs servo. I'm sure it ain't the master cly cuz if it was the pedal would go all the way down all the time . I'm guessing it's the abs servo that's leaking internally (bad pressure relief valve). has anyone had these symptoms before or can some point a light?

chrome91

iTrader: (1)

i dont believe the ABS system can do that, the cars brake system should be fully functional if the ABS fails. i would try bleeding it again, if that doesnt work i would almost think its the master cylinder again

arsonist63086

I suspected the abs actuator since the brake fad happened like once every other day and the MC had been replaced like 5 months ago (cardon unit). but now it does it often so I ordered the MC (ac delco unit) got it today. as for my reasons for pointing at the abs is that my bosses ford has a lot of brake fade .you press it and it slowly sinks after a bit of time holding it and the MC was replaced and fully bled.online research for his truck pointed to a bad abs unit leaking internally. so figured mine might have the same issue. so we will see after the new MC on my car .

imported_Nismo_max

iTrader: (5)

make sure you bleed it in the order of manufacture suggestion too. also i found that using a vacuum style bleeding procedure works best at lest for me. gl

Smiley's90Maxima

Yeh eh? I had drips of fluid coming from my front right fender. I actually had one a extra don't know where it went.

TheGodDerp

I've actually got the same problem with my 93 se, and it looks like it's eaten 2 actuators in 6 months, so I'm wondering if it's really a problem with weak abs systems or possibly something else breaking them.

Does anyone know what would be involved if we just delete the system completely?

Smiley's90Maxima

I was think i might have get that bond sealant. The one they used on the hovercraft and just seal the **** it stops leaking. You the powerful sealant?

TheGodDerp

If i had to guess, any sort of sealant probably wouldn't help given the location of the ABS unit. It's right next to all the cooling components and etc. so it must be dealing with constant heat cycling and isn't very durable, in the VE30 engine bay at least. Also, the unit itself has immense pressure cycling, which is what's probably causing the leak.

It could also be that the master cylinder or the abs controller is causing some sort of wonky pressure in the units that breaks them, because mine leaks from the front of the unit, or the left side if you're looking at it from where the Nissan plaque is stamped on it.

IIRC, people said to avoid the ABS cars where possible and I think I now know why.

The worse part is that the system doesn't detect that there's a leak, so you don't really notice unless you're looking for it.

arsonist63086

been forgetting to post me resolve. it ended up being a bad Master cylinder. I opened it up to see a failure point and wat I saw was odd. seemed like the brake fluid had crystallized inside. some was around the plungers and at the end of the inside of the cylinder also what appeared to be "mud" residue from the bad seals. just odd that the MBC had gone bad in about 5 months. (using AutoZone dot 3 fluid). I bled the full system till nothing but clear fluid came out to flush the system and readjusted the push rod on the vacuum booster too. in conclusion brakes like a new car now with instant braking..

as for removing the ABS actuator for standard non ABS is going to be to complicate as you will need to run new lines , new split valve , new master brake cylinder and now how to flare the new lines that you will add. luckily for me my abs actuator is still good and I make sure every once in a while on a empty street 😊 .