this morning I have a normal hard brake pedal but it takes temple-popping pressure to pull the beast up!
Pls pardon my "virginity" but my Rave1 has not yet arrived in the mail. Can someone link me to an overview of RRC brakes so I can understand what's going on?
I'm very suspicious of coincidence, but it could well be one here.
Warning lights? Well yeah! This has been the Standard Operating Sequence:
On start up, they all go out except for the ETC, Transmission Temp, ABS & park brake.
Release the park brake & the Transmission Temp light goes out. Apply the park brake & the TT light goes on. (Charming!!) The other 3 stay on. I've put it down to gremlins (ie dust) on a printed circuit board deep in the bowels of the beast.
After a few mins the 3 (ETC, ABS & Park Brake) all go out except for yesterday they came on in the middle of a 20 minute trip then went out again. Never happened before mid-journey- always happens when I park & re-start.
For now, it IS a vacuum boosted thingy , yes? Where's the booster? & where's the vacuum connection?
My Fergy is 61yo & still works for a living despite having nothing attached to it that warrants initials! eg ABS, ETC, ECU, EFI etc etc ad nauseum.
Methinks simplicity may equal longevity!
But then, I can't take mother to lunch in style on the Fergy!
Last edited by geodon; 29th October 2011 at 09:53 AM.
Reason: spelling
If you have ABS, then there's no vaccuum used in the brakes.
Brake pressure is supplied by the ABS pump & controlled through the ABS modulator. If the pedal is rock hard, then the pump's not working (& the accumulator is probably also out of pressure).
It's the Wabco unit, yes? So it's electrical not mechanical!
It's the thing that makes quite a loud buzzing noise when you switch on but ATM mine's gone VERY quiet!
Are they replaced or reconditioned?
I want to put a MultiMeter across it and maybe power it direct from the battery as a diagnosis. Does anyone know a link to the circuit for the multi-pin plug on the pump?
Geez! The devious variety-ie push, pull or just twist off- of those spring clips holding the electrical plugs on is enough to drive a man to drink! But then as W.C. Fields said: "My wife drove me to drinking- finest thing she ever did for me, yes"
Last edited by geodon; 29th October 2011 at 01:48 PM.
Reason: more info typo
The pump is in the foreground. The modulator has the fluid reservoir on top of it & the accumulator is the black ball shaped object tucked away in there.
If the pump doesn't run when the ignition is turned on, then you need to find out why.
They do wear & short out inside which blows the fuse, or it could be the temperature/overheat switch that's gone kaput.
It WAS making a noise while running but in my ignorance of noise levels, I've no idea how much is too much. It certainly drowned out the noise from the fuel pump!
Comments??
Last edited by geodon; 30th October 2011 at 07:50 AM.
Reason: more info
That plug is hooked up to a pressure sensing switch, hence the 5 pins.
It looks like 2 are earths & one is a feed to the ABS relay under a seat (not sure but I think it's the passenger) The other two actives are a pressure sensor (that makes sense) & a feed from the ABS ECU, but not sure why- surely the Modulator handles the wheel lock-ups? Maybe a "disaster" wire ie all wheels locked up=turn off the pump??
These inputs seem to determine whether the ABS pump runs by activating the relay.
As I see it, the ABS pump is permanently earthed & it gets current when the pressure sensing switch says so.
At this stage, I'll need to either measure the resistance directly across the ABS pump and/or try to "hot-wire" it (without burning anything!) to make sure it's dead.
Has anyone been down this path before??
Geez! We've come a long way brake-wise. My 3rd car was a '48 2.5 litre Jag with a Girling rod-activated mechanical system. I used to call them Tattslotto Brakes. The damn thing could do nearly 90MPH too!
Last edited by geodon; 31st October 2011 at 02:11 PM.
Reason: typo
I've tracked down the 2-pin connector to the ABS pump motor.
According to the Rave1 circuit, one pin is for earth & one is power supply to the motor.
So reading volts with my meter's +ve on the battery +ve, I should get 12 on one pin & zero on the other. I got 12 on both.
Measuring resistance across the the two, I got zero ie continuity?
Looks like the bugger has shorted out. Burnt armature? I might be lucky & find the brushes are worn to the short circuit stage & it's repairable but not if you can't get bits!
I switched on the ignition & checked the input- Not a sausage! I'd better check fuses & the PR9603 relay too!
I ripped into the pump expecting to find a burn-out & got suspicious when there was no Dirty Brown Smell.
I hooked up a hot wire to the motor & off it went. So when I measured an open circuit, the brushes must have been monentarily earthed. Memo: always hot wire it to make sure!
I resisted the temptation to throw it back together as before it stopped it was making enough noise to wake the dead & the bearing did not feel too smooth when I pressed down & rotated it.
About $US400 for a reco & I will replace the accumulator as well.
Oh BTW, Castrol GTLMA brake fluid is no longer made. What are we using now? Castrol say Super Response Dot4.
What stopped it? I hooked it up under the bonnett & went under the seat & swapped relays with the one next door & off it went! Yeah, a fricken dud Hella relay!
Huns.....0
Wabco.....1
I'll post again when I get it back
Last edited by geodon; 9th November 2011 at 07:25 AM.
Reason: add on
Master
Posting Permissions
Reply With Quote
Bookmarks