Bleeding brake system on F75 Fourtrack - Help


I recently had a rear wheel bearing replaced by my local garage, and afterwards they were unable to bleed the brake system to 100% pressure. The pedal travelled to the floor before applying the brakes. I was told that the master cylinder had become faulty, so I replaced it, to no avail. Still pedal to the floor before brake contact. I was told it must be faulty, so obtained another, still the problem persisted. I have now been told that it is probably the P&B Valve (proportioning and By-pass valve). It appears I can only go to Daihatsu agent for this, and I have discovered one for £152 + vat. Before I bite the bullit, has anyone else encountered this problem, and been able to resolve it any other way. The manual that I have does not give any specific instructions on special requirements to bleed the system. Any help would be much appreciated. Thanks. Mike Cooper

With the engine stopped, pump

With the engine stopped, pump the brake pedal several times, about thirty, this will depressurise the vacuum system.

Begin with the rear wheel furthest from the master cylinder, locate the BPV and sprag it open on the lever, this will allow full fluid flow. This will have a lever connected with a sprung lever to the body and axle, it can work two ways so pull or push it to see which way it operates.

Bleed the rear brake fully, then go to the opposite rear brake and bleed this fully. Repeat this with both the rear brakes.
Move to the front brakes, do the one furthest from the master cylinder, then do the remaining one.

Repeat this with both fronts, do not forget to remove the sprag from the BPV and try with the engine running, this should cure the problem.

Bleeding brake system on F75 Fourtrack - Help

Hi guys, and many thanks for the comments. I believe we have some crossed wires here as the item you refer to is the LSPV (Load sensing proportioning valve) This is not fitted to my fourtrack, and I believe I am correct in saying, is only fitted to the pick-up version. The unit fitted on mine is a sealed unit, and sits on the bodywork just below the Master Cylinder. One single pipe is fed to the rear offside wheel cylinder, and exits from same across the back axle to the near/rear. No other equipment is situated along these lengths of pipe. There is no provision to bleed the B&P valve, other than loosening connections to the pipe runs, and in desperation, we have tried that. Regards to all. Mike

They are the same thing, some

They are the same thing, some call them contact breakers, others call them points, its the same with the LPV, they get called different things.

Your vehicle should have one fitted, so its been removed and replumbed, nothing unusual. Have you bled the master cylinder itself, they need bleeding before the brakes, original equipment items have a bleed nipple fitted, aftermarket items do not.

Place a small tray under the outlet pipes and crack the pipes with the pedal down, hold it down until they are tightened. Do this several times and it should bleed it.

Hi and Welcome


Reading this post makes me think the garage/mechanic is not sure of how to bleed the system, as it seems a new component is required each time. From looking at previous posts it seems the major problem with bleeding the brakes is opening the proportioning valve to allow fluid flow to all brake cylinders.

Edward (ews) '92 Fourtrak 2.8 TDX

It is a problem, particularly

It is a problem, particularly if the vehicle is on one of the modern lifts and no weight is on the wheels, this closes the valve to its minimum setting. This lets very little fluid through, and the BPV tends to trap a large amount of air.
As the BPV operates on compression of the rear end due to the weight being carried, it opens and closes in relation to this weight, and biases the braking effect to the front wheels.

Simply spragging it open gives full flow to the rear brakes, and it prevents trapped air from forming. As we already know it takes little trapped air for rubbish brakes.

Bleed the load proportioning valve as well

The load proportioning valve will be bolted to the inside of the chassis rail, just in front of the off side rear wheel. The valve has its own bleed nipple, you've got to get the air out of here as well to stand any chance of success. The early valves didn't have an actuating lever, just a steel ball inside, on a slope held back by a weak spring. When the rear of the vehicle is weighted, the angle of the slope reduces and the ball becomes easier to push against the spring which allows greater breaking force to be transferred to the rear. You also need to give the pedal a good hard push with a foot (like emergency stop) to the floor during the bleeding procedure, a gentle push won't shift the ball in this valve so won't bleed the rear.

Trust me on this, it once took me 12 hours to get this right.



Bleed the longest run first. Then the next longest. Finish with the shortest.
Tighten the nipple at full pedal before releasing the pedal. Check the plastic tube being used has no pin prick holes - often the reason why air is being sucked into the system.

brake valves


Just had a look in my Parts Manual CD (not the service manual). Noted that dependant on year/model the F75 series could have had no balancing valve or a "P" Valve (Proportioning Valve) or a "P+B" Valve (Proportioning and Bypass Valve) or if it was a Pick Up version a "LSPV" Valve (Load Sensing Proportioning Valve). The location of "P" valve varied from near the master cylinder to the pipe run to the rear axle, same for the "P+B" valve . None of these seemed to have a "bleed nipple" listed Also looked in the Service manual, no mention of a bleed nipple !!!!, though the different valves are refered to. Added to the possibility that a previous owner may even have removed this item !!!!.

Am I glad I got my local service man to do my brake fluid change !!!!!, must ask him about this !!!.

Edward (ews) '92 Fourtrak 2.8 TDX

Now Ajcaine has jogged my

Now Ajcaine has jogged my memory i can remember four variants of these valves.

As already mentioned the rear nearside body mounted valve, and the bulkhead mounted version of the same valve, the other variant was the front offside chassis mounted variant. These were all the ramp type with the spring mounted ball.

The final variant is the body or axle mounted variant of the lever type on European models.

Some imports had a master cylinder with this integrated, and others had it mounted on the inside of the chassis rail next to the clutch actuation lever.

Brake bleeding problems

Thanks for all the comments guys. I contacted a Daihatsu main dealer today, and he was only able to offer advise as described on here. He did not know of any problems with bleeding the system, and had only done one yesterday. So there we have it. When I get another slot in the weather window, I will have another go. Anybody want a cheap fourtrack with dodgy brakes????????????