PMIII actin up.

[GangstGP]

the new car I got has a strange intermittent problem. it will be braking just fine, then suddenly it loses pressure. I will be trying to slow and nothing then suddenly a moment or two later it brakes fully and rapidly, but there is a delay before it works and this only happens every 3-4 tries otherwise it works good. why would it lose pressure like that? is that the acumulater, relay, pressure switch, or bad pmIII, or sensor related. I think the last owner just got a prior unit right before it sat for 6 years.

I replaced the 1 relay in the upper box, but the one down on the right side of the unit pointing down may be bad. what you think?  its kind of an on/off problem like it works, then I turn a corner and brake again then it dont work, so I pump the pedal 1-2 times and then push hard and suddenly the pressures back and we stop.   

[z284pwr]

Mine had the problem, it sucked, they wouldn't work, so you are like :icon_eek:  then you let up, press again and almost smash your head into the steering wheel because you press so hard and they work :icon_rolleyes:

This is just before the entire PMIII stopped working and it went to no power at all....

Accumulators go bad and should be replaced like every what 2 years?  Maybe that?  I'm not really up to par on them, I don't like them much, big and expensive!!! :icon_evil:

[GangstGP]

damn, the reservoir was low. that explains alot there. narrows it down at least to a leak somewhere. first thing I will check is the rear proportioning valve or a pinhole in a line. never had to replace a rear valve but heard its common.  oh well, at least I didnt fry the pump running it low. :bonk:

[Prospeeder]

makes some sense, like its low and the pump is fed fluid then it hits a dry spot (like sloshing from being low) and goes dry and you lose brakes.

[z284pwr]

You would know a rear proportioning valve problem, as brake fluid would be on the ground below the car....

Just don't get unlucky like us and have brake fluid eat through the lines of the Nuetral/Park safety switch, that one is really FUN to get with the engine/transmission in the car..... :icon_rolleyes: You get to do it with no eyes at all :icon_eek:

[GangstGP]

well, its going somewhere. :icon_confused: I filled it last night and drove it around with no problem. then today I was out and about and the thing stopped working all together. man its gonna suck if that was all it took to burn up the pump. I havent checked the fluid yet but its gotta be fixed soon, like now. I got a spare PM III unit that I can try thats off an 89 tgp but doubt it will work good. think positive :icon_rolleyes:

[GangstGP]

damn, I kinda fixed it.

I popped the top and there was still fluid in it. so I checked the fuses and one of those weird looking pink 30A fuses with the window on it was blown. so I go to the parts store and replace it with another, it runs for like 3-5 sec. and pops so I go back in and grab a 40A and slap it in. the pump comes on again and sounds kind of worn then a light stream of smoke starts coming out of the right side of it  :icon_lol: and the copper in the clear fuse window changes color like 3 times, I can tell its about to pop so I yank it.  but the pump was pumping though, so I wiggle some wires around down by the heat shield,  stuck the almost blown fuse back in and it runs for like 5 more seconds and the pressure switch kicks  :icon_cool:.

[Prospeeder]

lol i think u need a new MC

[z284pwr]

Time for a custom 1 off brake setup....

*This is what we will be doing when the Prior unit we just got dies*

[GangstGP]

no, its fine now. like I said all it was for now is a short down on the wires down by the heat shield, I saw the smoke come up from down there. when first got the car I had to unplug the harness and the wireloom crumbled off and I never replaced it yet. so thats obviously the solution. I have seen the heatshield cut into the wire jackets before.

[TurboGTU]

Easy now there bud. Don't just step up the fuse amprage like that. You can burn up your wireing like that. I think the motor is gone. If they constanly work hard..they will burn up. I think yours just gave up the ghost. Had a Dodge minivan come in with it blowing fueses now and then. They thought it was a short around the wring. I ohmed the fans and sure enough...one was alsmot zero ohms. Got the motors in and costomer has been happy since.

Beeing lown on fluid can be a crack in the PMIII unit itself. Its a known issue. Im doing the dounting taks of going to regular brakes. At least I know I'll have brakes when I need them most.

[GangstGP]

yea but the accum. can be replaced and this might be one of the prior  units, I am thinking it might be a leaky brake line or proportioning valve.  the fuse blew again today so I am giving up on this accumulater. Im going to remove and inspect it now. the prior one is supposed to be more crack resistent so they say.  But yea, the pump burned up I think.  :icon_cry:

[GangstGP]

pulled the dang thing out today and the pressure switch had been pouring fluid out of it for the last six years. the fluid has been corroding plastic switches and peeling paint. the previous owner did put a new prior unit in 500 miles ago I just found out. damn, from personal experience and what I have heard they must not do much testing on their stuff before sending it out. Is prior the only place to get the pressure switch from?

[GangstGP]

Well, I fixed it with a grand total of $5! I had to buy 2 new fuses for $2.50 each.

The only thing is I had to take a factory accumulater assembly off my spare PM III and use it.

anybody know why the prior unit would be  leaking out the accum. threads and the pressure switch when its brand new? the fluid ruined my shift indicater switch. lucky I had a spare. they must not be sealing the threads with the right compound because they leak like a siv. which pressure switch do they use? it was leaking out the plug. how could a 16 year old pressure switch not leak a drop, but a $600 prior unit comes with a leaky one? twice?

cant wait to pull off my other Prior unit from my other car to find the same mess. It was leaking since the day I put it in only its a slow leak that somehow stopped leaking.  Thats like $1200 to them for 2 #^%$#'d up pieces of crap. I dont know, It would be better to have access to their parts then to not, so I will shut up now.

[LukeZ34]

So what was your secret to getting the Prior accumulator off?
Ours is torqued on so damn tight that I can't even budge the damn thing. Any suggestions?