Last 2 days have started van from cold (2nd occasion after an hr break)and started to drive off - however on touching brake pedal rear o/s wheel locks and van dips heavily on front offside
I go forward and backward a few times using brake - then get fed up and set off and problem is gone once driving properly
Assume its a split circuit and one circuit stops working for some reason - servo seems to double in efficiency on the one cicuit ie
the slightest touch on pedal and it happens
Has anyone any suggestions as to where to start looking as if it happened on the road an accident would be likely I think
Its a 92 4wd auto version
Thanks
Chris
- (#8214) chris turner, 27 Apr 03 13:36
possible wheel cylinder failure take wheel/brake drum off check for brake fluid contamination.
- (#8215) daryl lewis, 27 Apr 03 14:10
Thanks Daryl
Was 'hoping' that may be the last thing I have to do.
No warning lights on and its only happened briefly twice when cool
I thought that a circuit would have to fail big time to isolate itself - I looked underneath but no sign of fluid dribbling - though I'll check daily
Noticed a couple of boxes underneath - one pan shaped and I think the other squarish with vac tubes hooked up and linked to braking system - dont know what they are but as I am suspicious of the vac system at the moment and wondered if it was a link
If you turn out to be right - well I'll add it to the list of things to sort!
Chris
- (#8216) chris turner, 27 Apr 03 15:53
As daryl says, could be fluid contamination. Could be effecting the Load Sensing valve situated near the rear diff. Even if checking the wheel cylinder proves nothing, I would be inclined to purge the brake fluid. It's supposed to be done after 30k miles anyway. As the vehicle is new to you, you won't know its history so definitely a job worth doing. When bleeding, do the LSV last.
- (#8280) Ian Dunse, 28 Apr 03 8:28
Thanks Ian
I had never considered that old fluid may be causing the problem as the pedal pressure feels good...
The two large (brake related) air container like devices mounted midway under the van hooked to vacuum tubes - do you think the problem may be related these or other vacuum issues?
In other posts I have highlighted possible vacuum probs ie:possible variations on level of vacuum affecting idle/idle up speeds - base speed can vary by about 200rpm at running temp (though it tends to be one or the other only noting the difference at traffic lights etc. operating temp is also affected by whichever idle speed it chooses).
For safety, fluid leak checks need doing until resolved - but the fluid flush I was hoping to leave for a while unless essential (hate doing as though its on service schedules I have never noticed any obvious improvement)
I'd be interested in any thoughts on the vacuum issue as thats what I suspect (also ties in with a current problem)- but I have no experience or understanding of these vaccum boxes - can anyone enlighten me further?
Chris
- (#8281) chris turner, 28 Apr 03 18:07
the "air containers"? one has a wire attached, no? it's a vacuum reservoir with a warning switch. Pump the brakes, turn on ign (h/ brake off) and start up. the h/ brake warning light should come on, and go out when the engine gets up to speed.
The other item is probably a reservoir too, the 4x4 townies have one near the transfer box for it's supply
- (#8282) david miller, 28 Apr 03 23:38
try to pump the brake pedal repeatably with the engine running, gear in park & handbrake off. if the braking warning light comes on & off then it could be a leakage on the master cylinder rear, this does not show as a brake fluid leak as the fluid just goes past the seal. another characteristic is no poor braking when reversing slowly
- (#8283) john collier, 30 Apr 03 4:36
Re
last two posts - yes and fortunately no
However the pedal reaches its stop (where is the stop as its a long way from the floor?) very easily with each push. Never noted this previously.
Any other suggestions? if not I'll pursue Daryl and Ians suggestions (which I have been avoiding!)
Have an 'easi bleed' which is no pleasure to use and not that easy.
Saw this product on
http://www.motiveproducts.com/
which looks ideal. Anyone know if something like this is easily available in the uk?
Chris
- (#8284) chris turner, 30 Apr 03 17:02