100 series hydro boost pump.....

[Reiner]

Hi all, just picked my 2003 model 100 series from Toyota after they checked out why my ABS warning light comes on at times. Been told that the computer is telling them it could be a faulty hydro boost pump being damaged by somebody replacing the brake fluid with the wrong stuff.
If the fault comes back I need a new boost pump at a cost of close to $3000 plus labour and stuff
So I said how about we replace the brakefluid for starters so it cant do more damage. Come back was.... it is to late the damage is done. I said but you don't even know if there is damage or if it is caused be using the wrong fluid so can we please change the brake fluid to the correct one to prevent further damage.( It had green stuff in it which Toyota don't use)
It took some talking to get the car booked in for a complete brake fluid change. So that is next wednesday the 20th of August.I had a 40 series Landcruiser diesel for 22 years and still have a 94 model cab chassis diesel (HZ) and never had much drama with those cars. I just bought this one with 160.000 km on the clock and in real good condition.
I don't feel like paying $3500 for a brake thing and I never had ABS before so can I just turn the ABS of maybe by pulling a fuse or is there a way to fix this booster thing cheaper? Wrecker maybe?
Any feedback would be great Thanks

 

[Doodle]

In the UK, pulling the fuse on the ABS would make the car fail it's yearly test - I'm guessing things are a bit more lax on the other side of the world.

 

[BobMurphy]

If the electric pump that provides your brake servo power fails you get the ABS warning light, Brake warning light and a warning buzzer . . You also have next to no brakes .

Its a vital piece of equipment (whatever happened to the good old, simple, vacuum servo running off the vacuum pump that powers the EGR Valve ??).

Why do cars have to get increasingly complicated - and expensive to repair??

Rant . . Rant . .

Bob.

 

[Reiner]

In the UK, pulling the fuse on the ABS would make the car fail it's yearly test - I'm guessing things are a bit more lax on the other side of the world.

We don't need to do them here in qld Australia( only when you sell you car) but I am wondering if it would affect the brakes performance

 

[Crispin]

(whatever happened to the good old, simple, vacuum servo running off the vacuum pump that powers the EGR Valve ??).

Bob.

Sorry for the hijack -
Bob, I thought the reason diesel's had an electric pump was because there was no vacuum that could be used as there is no butterfly to close hence no vacuum.

 

[Chas]

We don't need to do them here in qld Australia( only when you sell you car) but I am wondering if it would affect the brakes performance

 

[BobMurphy]

Bob, I thought the reason diesel's had an electric pump was because there was no vacuum that could be used as there is no butterfly to close hence no vacuum.

You are right in that there is no vacuum from the inlet manifold, as there is on a petrol-engine car, but Toyotas have a vacuum pump low down on the front of the motor.

My '95 Colorado' has a vacuum brake servo and the EGR valve is operated by solenoid valves that use vacuum to operate the valve on the exhaust feed.

My 100 has a vacuum pump as well, and uses the same solenoid valves to control the vacuum-operated EGR valve. For some reason Toyota decided to go for an electric pump and a pressure reservoir for the brakes instead.

It might have something to do with the space available but it results in one hell of a single point of failure.

Bob.

 

[cavanmick]

Mercs and newer pajeros are the same,nightmare of a set up,anything with a motor in it has a finite life so why not just stick to low tech reliable.

 

[frank rabbets]

Bob, you think the 100's are complicated. My wife just "touched" a wall in our new golf and a warning came up saying to take to dealer. She had dislodged the anti collision radar dish which needed resetting and recalibrating. I think the Eurofighter has one of those! It put the brakes on the other day as it thought my closing speed on a moving car in front was too high.

I told my wife to sign the papers at VW with "FOC" underneath. They didn't check her signature and weren't very happy when we picked the car up. Long story but they owe me £3000 in my book.

 

[uHu]

Back to the 100's brakes.
I believe the booster-brakes of the 100 gives more braking force than a vacuum system could give. At least the pressure is higher than the 1 bar (theoretical) that a vacuum system could give.

Anyhow, without an operational booster, you have virtually no brakes at all, only a very small effect on the front wheels, if you have strong quadriceps.

One known problem with the booster motor is that the brushes wear out, sometimes at only 2-300 k km. It could be possible to change them, but they are not replaceable according to t0yota. There are some threads on this on mud.

Wrecker parts is a good option - then you get the master changed as well (otherwise, you can get the piston seals as maintenance parts)

Btw, the booster will not manage to keep the pressure up if you pump the brakes rapidly several times within a short time, and that will give you warning lights.

How does the booster sound when you turn on the ignition (don't start the engine) after emptying the booster's pressure? That could give you some indication on the state of the motor and pump.

 

[Reiner]

Back to the 100's brakes.
I believe the booster-brakes of the 100 gives more braking force than a vacuum system could give. At least the pressure is higher than the 1 bar (theoretical) that a vacuum system could give.

Anyhow, without an operational booster, you have virtually no brakes at all, only a very small effect on the front wheels, if you have strong quadriceps.

One known problem with the booster motor is that the brushes wear out, sometimes at only 2-300 k km. It could be possible to change them, but they are not replaceable according to t0yota. There are some threads on this on mud.

Wrecker parts is a good option - then you get the master changed as well (otherwise, you can get the piston seals as maintenance parts)

Btw, the booster will not manage to keep the pressure up if you pump the brakes rapidly several times within a short time, and that will give you warning lights.

How does the booster sound when you turn on the ignition (don't start the engine) after emptying the booster's pressure? That could give you some indication on the state of the motor and pump.

thank you for your great reply. I get a squirling noice from under the bonnet that sounds to me like a dry pump. But somebody said to me start the car with pressure on the brake paddle and I have not seen the warning light come on since I started doing that. No idea why but it seems to work.
saying that I have driven the car maybe 100 km and started it maybe 6 times but so far so gut.
any idea what's going on there?
cheers

 

[frank rabbets]

It's the surface area of the diaphragm that will determine how much psi you will get on a fixed diameter piston so perhaps they ran out of space.

I did not realise I had power brakes!

 

[uHu]

@Frank: Yes, of course you're right, it's the square that counts.

@Reiner: "squirling", that's a good description of the sound. Mine sounds like that as well - I suspect it's on it's way out. Not too worried tho', as I have a spare one waiting. Maybe I'll just change it one day, rather than waiting to be stranded.

Also, on my 2000, the pressure would keep overnight, with the pump running maybe only 3 secs when starting in the morning. On my 2004, the booster pressure is gone after 1/2 hour, and the pump runs for maybe 20 secs to fill it up again. This, of course, will wear the motor faster.