[Buffalo1992]

Hello fellow members.Am writting from Tanzania East Africa where the Estima is regarded a rare option for a bus due to scarcity of spare parts.
I own a 92 diesel model,4WD.
I don't know whether is had 3ct or 3tce type of engine,but all the same it is 3ct according to the mechanic.I have had so much problems with this bus to an extend I just became used to it.I love it.
To the point.Recently I did engine swap after the first engine got wrecked after the cam belt broke at high speed.
Somehow the new engine is different from the former since it had no brake vacuum pump on the cylinder head side.
The mechanic did a nice job though I later discover an idle pipe under the front passenger side that sucks air in when engine is on.
Some mechanic told me it came from the brake vacuum pump,a claim supported by the same mechanic who performed the engine swap.
Dar es salaam is a very hot coastal town with degrees above 35.
When air con is switched on,the brakes don't work normally and they would harden on the pedal and the brake light on dashboard flashing the bus would just continue moving like a stone only to be stopped by an obstacle infront if any.With air con off brakes function normally.
The truth is the brakes are being assisted by vacuum generated ny the alternator while the brake vacuum pump sucks air idly undr passenger seat.The brake vacuum pump is under the driver's seat.
My bus has no ABS.
I was thinking of piping the brake vacuum pump to the front side just behide the battery where the vacuum from the air con joins the another pipe from the break master or in other word the bowl like object that has the brake oil bottle attached at from.
Can some one assist me what I should do?
Frank

[lucifreak]

hey buff!

            OK!! first of ive never seen the engine types swapped like this and am not sure if its really workable so ill with hold my judgement, 

            To be honest i was working on a reply for you,but have decided that really its a true safety hazard especially with it affecting the braking capabilitys as badly as it is.

            My only advice can be to seek professional help and get it sorted correctly asap.

            Others may reply so ill leave it up to them to decide on theyre own experiences.

           

          







             

This post has been edited by lucifreak: 29 January 2010 - 06:12 PM

[Townaceclive]

The brake servo works of the vacuum pump, The A/C using vacuum also to operate. I suspect that one of the pipes is off/split or that a one way valve it around the wrong way.
You need to check the vaccum pipes for air tightness.

[Buffalo1992]

Thanks lucifreak.
Just a word of correction.By swap I mean change of engine,from a faulty 3ct diesel engine to a different but used and healthy 3ct diesel engine.What makes me think its different from the original engine is the used and healthy engine had an electrical injector pump compared to the original which had mechanical pump.I retained the mechanical pump instead of the electrical one though and its the same am using on my estima in my adopted engine.
The piping system looked different too,and the additional brake vacuum pump on the new engine surprised me too.
I think I should be having the same diesel engine,3ct upgraded somehow maybe for 94,95 or 96 versions.
So this brake failure problem seems to be caused by low vacuum facilitation by the alternator,thus the need for bringing in the under-driver-seat brake vacuum pump facility into the braking system.
Question is,should we cancel the alternator brake vacuum facility and opt for the brake vacuum(I have photo of this vacuum pump under driver seat) such that the brake booster recieves vacuum assistance from this pump alone in isolation of the alternator or should both be in use?

[Buffalo1992]

Townaceclive, on 29 January 2010 - 07:10 PM, said:

The brake servo works of the vacuum pump, The A/C using vacuum also to operate. I suspect that one of the pipes is off/split or that a one way valve it around the wrong way.
You need to check the vaccum pipes for air tightness.

Thanks Townaceclive.
Your suggestion could be right though I have to tell everybody reading this topic that during the engine change operation,no new pipes were introduced into the braking system because as I said earlier that the metalic pipe from the brake vacuum pump is still open because then it was not fitted with any pipe to anywhere.You can see it when you remove the passenger side cover and if you chance to place your finger or block it with a finger it pulls inwards on your finger tip like a suction action.
Another thing to consider is that during the engine change the mechanics concetrated their surgery activities only where the original engine had been,and had no reason to interfere with parts under the bonnet like the alternator and the piping from it to the brake booster thing.
Maybe that pipe from the alternator needs attention to check for cracks or damage.
I will do so tomorrow morning since its friday 15 minutes to 23 hours.
Meanwhile your contributions will be highly appreciated.
The question one driving my estima will ask is WHY SHOULD THE BRAKES DISSAPPEAR WHEN Air Con IS ON?

This post has been edited by Buffalo1992: 29 January 2010 - 07:52 PM

[Townaceclive]

The original engine vac pump is on the alternator the new engine has one on the engine sticking out of the rocker cover.

Why the vac goes when the A/C is on is that there is somewhere where air gets in and cancels any vacuum,

How long before the servo works once A/C is switched off?

[Buffalo1992]

Townaceclive, on 29 January 2010 - 11:14 PM, said:

The original engine vac pump is on the alternator the new engine has one on the engine sticking out of the rocker cover.

Why the vac goes when the A/C is on is that there is somewhere where air gets in and cancels any vacuum,

How long before the servo works once A/C is switched off?

Bravo Townaceclive
You have now hit the nail on the head,one is that the original engine has vacuum from the engine and the new enginehas a vacuum pump sticking out on the rocker cover.This vacuum pump sticking out on the rocker cover is not utilized at the moment in my estima.
Another point and one which I can share with you is that there could be vacuum cancellation probably by some air getting in.
Today I will first have the mechanic check this air intrusion possibility,also check for piping faults like cracks.

Need I use the rocker cover vacuum pump together with the alternator pump or should cancel either when the air intrusion is rectified and employ one of them singly?

You asked when does brakes resume after switching off air con.Immediately is the answer,say like a matter of seconds.That is why I used to think that the air con was draining the alternator power to generate vacuum.My car electrician tested the alternator and found it ok as far as power generation is concerned.However we didn't test the mechanical health of the altertnator.
This reminds me that about the power steering not effeciently doing what its supposed to do after negotiating a corner,the steering wheel delays in correcting the turn to straight course so I have to do it by myself as in a bicycle.Few days ago I noticed wetness(bleeding) on one of the pipes for steering hydraulic fluid leading to or from (I can't exactly say which is the case) the vacuum on the alternator,I suppose could be the one reason causing vacuum loss. Hope you understand.

This post has been edited by Buffalo1992: 30 January 2010 - 04:29 AM

[buffallobob]

Buffalo1992, on 30 January 2010 - 04:07 AM, said:

Bravo Townaceclive
You have now hit the nail on the head,one is that the original engine has vacuum from the engine and the new enginehas a vacuum pump sticking out on the rocker cover.This vacuum pump sticking out on the rocker cover is not utilized at the moment in my estima.
Another point and one which I can share with you is that there could be vacuum cancellation probably by some air getting in.
Today I will first have the mechanic check this air intrusion possibility,also check for piping faults like cracks.

Need I use the rocker cover vacuum pump together with the alternator pump or should cancel either when the air intrusion is rectified and employ one of them singly?

You asked when does brakes resume after switching off air con.Immediately is the answer,say like a matter of seconds.That is why I used to think that the air con was draining the alternator power to generate vacuum.My car electrician tested the alternator and found it ok as far as power generation is concerned.However we didn't test the mechanical health of the altertnator.
This reminds me that about the power steering not effeciently doing what its supposed to do after negotiating a corner,the steering wheel delays in correcting the turn to straight course so I have to do it by myself as in a bicycle.Few days ago I noticed wetness(bleeding) on one of the pipes for steering hydraulic fluid leading to or from (I can't exactly say which is the case) the vacuum on the alternator,I suppose could be the one reason causing vacuum loss. Hope you understand.

This is not just as simple as the belts slipping is it ? as for the steering pump that is not the bit on the alternator with the oil pipes they are for the vac pump. a supply to and from the engine to lubricate it,
Did your man connect the pipes from that pump to the engine one would have been oil feed and the other he would have had to swop the side cover from the old engine with the oil filler on it to be able to connect the return pipe.
The power steering pump has the fan bolted to it.
bob