ABS pressure switch

[lotus4s]

Did any of you guys ever find a source for these? There was some discussion a while back and someone was looking into having some manufactured but I never heard if anything ever materialized.

They are becoming as scarce as hen's teeth here in the US and several people are looking for them. If nothing is being done, I may look into the possibility of having some produced.

Any help is appreciated.

Jim

[greekmix]

Jim,

This part has been an issue for many moths now. No one seems to know where can we source it any longer even Lotus and GM has now stopped providing the part.

I can tell you that I know of a single part available in Australia and if that goes I am not sure what we are going to do.

Please contact me if you find a solution to this item as I would like to put it back on the cataloque.

Tony

info@lotusesprit.com.au

[DanR]

Do a search. Mark in Canada came up with a clever fix.

[Jonathan]

http://www.lotusespritforum.com/forums/ind...0&start=120

[lotus4s]

I know of the fix but it doesn't work in all cases. I know of at least one owner here who has tried it several times and his switch is still not working...

[Dasar7]

Yep, I tried to clean up my switch per Mark's method with my mechanic just this week.......no joy!!

My ABS & brake system 'seems' to work fine, but cannot get that #*%#& ABS light to stop blinking.

[t70]

it's possible it's not the ABS switch.. it is possible that it's just a wheel speed sensor. I had both problems at once. The first was my fault (the wheel speed sensor was not properly clipped in and wasn't making contact) and the second was because of the pressure switch. If you're brakes are wooden.. then it's the pressure switch for sure... if they pressure up properly (kick back at you when you push the brakes) and the pressure is regulated properly (the pump isn't coming on all the time which would probably be the nitrogen capsule which is from an 88? jaguar) then it's probably not the pressure switch.

P.S. Jim.. I had a local GM dealer source the part at one point... but it may take some additional work for me to get it again... As I recall it was from a 92 olds cutlass?? I'll have to re-check that though.. This does tell me, however, that there are still some switches available... and the pressure switch should be an on/off type, not a resistance type, so any pressure switch that fits the hole should work.

[lotus4s]

Mark,

You can't just use any pressure switch. The system works at very high pressures and the switch activates the pump at 2200 psi and shuts off at 2700 psi.

The sensors can cause an abs light but our problem with the one we are trying to fix is the pump running continuously...

The part cross references to several GM vehicles; 1988-1991 Buick Regal, Olds Cutlass, Pontiac Grand Prix and Corvette. The GM and AC/Delco parts lists now show the item as being no longer available with no listed options available. The only way to find one is to start calling GM parts dealers around the country and hoping you get lucky and find one sitting on a shelf somewhere or possibly used part suppliers or junk yards.

I'm aware of a couple of people looking into the possibility of having some manufactured but nothing definite at this time.

Edited December 1, 2008 by lotus4s

[Daniel]

You need to open the front compartment, stand outside the car and pump the brakes......

after a few pumps, you'll hear the accumulator kick in, stop pumping and wait for it to stop.....then pump again until it kicks in.

do this a few times, and if it works all the time, and if you've never experienced the brakes go wooden, then the switch is fine, and as Mark says, it's more likely a sensor.

[bzguy]

Did any of you guys ever find a source for these? There was some discussion a while back and someone was looking into having some manufactured but I never heard if anything ever materialized.

They are becoming as scarce as hen's teeth here in the US and several people are looking for them. If nothing is being done, I may look into the possibility of having some produced.

Any help is appreciated.

Jim

Nick Fry (fflyingdog) had a possible replacement part, I asked him for an update ...

[t70]

Jim.. I recognize not "ANY" pressure switch will work... what I meant was any brake pressure switch that fits should work right? I don't know the pressures of the rest of the systems out there... but I would think they are a similar range?

[lotus4s]

Mark,

Not necessarily, the Delco Powermaster I system which has an almost identical looking switch that operates in the 500-600 psi range.

Daniel, thanks for your input but I'm pretty familiar with these systems and how they operate in our cars and the problem we are working on is not a sensor problem. The sensors have nothing to do with the pump running continuously. That is most commonly caused by a bad accumulator or pressure switch..

[t70]

Thank-you Jim! I had no idea that there would be two different pressure ranges for this kind of system. Very good that you've cleared that up!

[fightingtorque]

One thing I would add: There were two specs used by Lotus, the early one and the late one, the pressures were different.

I started with the late one but Lotus could only get me the early one as a replacement.

A downside is that the brake lights come on sometimes when parked, and this can flatten the battery. As a temporary solution (just about a year so far!) I put a bungee cord from the pedal to the steering wheel spoke. I do this while I am letting the turbo cool down so it has become second nature, but in general I intend to fit an extra return spring to the pedal.

There may be an upside: I used to bitch about the oversensitive ABS which used to let the brakes off whenever you went over a bit of a bump. Not ideal when driving on Norfolk country lanes and wanting to slow down and tuck into the uneven nearside road edge to squeeze between the bank and the oncoming trucks.

My impression, although I would need to do a proper A-B-A test to be sure, is that since fitting the different spec sensor the ABS has worked in a more appropriate fashion. The different pressures could be a factor in the way it operates since the ABS has to manage the application and release of this pressure.

Just my thought about the two switches, but can't help you with a source for either. I had to get mine from the Lotus factory, with a little help from Mr Bibs.

GF

[DanR]

Was inspecting an 05 Toyota Prado yesterday. They also have a nitrogen charged braking system like ours. Now wonder if there is a similar pressure switch on those which could adapt across.

Anybody au fait with the Prado brake system?

[lotus4s]

GF,

I think your problem with the brake pedal may not be related to the abs switch. On the two different switches that were used the earlier one has a black plastic housing and the later one has the gray plastic housing. And you are correct that the pressure ranges are slightly different.

I've been using the earlier (black) switch on my car for about a year and a half now and have had no problems with the pedal and brake lights. You may just need to adjust the switch at the brake pedal.

Cheers

[fightingtorque]

ah, of course! on a normal car the brake lights tend to work from a pressure switch, but I guess on an esprit it works off the pedal arm and can be adjusted? will have a look at that. thanks!