300Tdi Vacuum Pump

[Bushie]

After only 4 months my vacuum pump has packed in again. 3rd one since 2008. Looking on the web there seems to be plenty of evidence that the genuine Wabco ones are very poor parts.

Anyone have any suggestions for another breed ? Are there other makes available ??



Martyn

[PAT303]

The only trouble I've ever had was the screws came loose on the cover plate.A bit of thread locker and never had a problem since. Pat

[Bushie]

Not that style of problem, they have each gone noisy and stopped producing any vacuum. Something is failing internally, will pull this one apart (if I can work out how to get into it) any try and see what lets go.

A bit of research suggests the internal valves come adrift and get destroyed by the plunger.



Martyn

[abaddonxi]

http://www.aulro.com/afvb/good-oil/42516-brake-vacuum-pump-300tdi-rebuild-instead-replace.html

Any links to the Wabco pump problems?

[slug_burner]

There is an amount of information on taking the pump apart and repairing it, however if you do not like the prospect of using the same type of pump you could try a belt driven vacuum pump. Belt driven pumps are often coupled to the alternator such as with the TD5.

[Marshall]

Found a couple on e-bay...

Land Rover Discovery & Defender 300 Tdi Vacuum Pump (eBay item 200522018804 end time 20-Mar-11 10:10:11 AEDST) : Cars, Bikes, Boats (http://cgi.ebay.com.au/Land-Rover-Discovery-Defender-300-Tdi-Vacuum-Pump-/200522018804?pt=AU_Car_Parts_Accessories&hash=item2eb00b2ff4)

Vacuum Pump Discovery 300TDi (eBay item 230575658196 end time 20-Mar-11 12:59:58 AEDST) : Cars, Bikes, Boats (http://cgi.ebay.com.au/Vacuum-Pump-Discovery-300TDi-/230575658196?pt=AU_Car_Parts_Accessories&hash=item35af6154d4)

[Bauke]

you could always get rid of it all together and buy a electric vaccum pump they are available on ebay and i can tell you they work very well, then make the old pump an idler or get a shorter belt if that works

[Bushie]

http://www.aulro.com/afvb/good-oil/42516-brake-vacuum-pump-300tdi-rebuild-instead-replace.html

Any links to the Wabco pump problems?

Oil leaks from the pump end haven't been a problem (they don't last long enough)

Wabco vacuum pumps (http://forum.landrovernet.com/showthread.php/198911-Wabco-vacuum-pumps)

Land Rover Forum in Africa • View topic - Faulty Wabco Vacuum pumps (http://landyonline.co.za/landyforum/viewtopic.php?f=6&t=2781)

300 Tdi vacuum pump failures - SA 4x4 Community Forum (http://www.4x4community.co.za/forum/showthread.php?p=651833)

Different types of failure but dont do a lot to instill confidence in the wabco unit.

Martyn

[abaddonxi]

All these problems seem to be fairly recent. I wonder if there was a bad run, or a change in factory.

Just about the only thing that never needed repairing on my 300tdi was the vacuum pump, and it came to me having been rebuilt.

[one_iota]

Oil leaks from the pump end haven't been a problem (they don't last long enough)

Wabco vacuum pumps (http://forum.landrovernet.com/showthread.php/198911-Wabco-vacuum-pumps)

Land Rover Forum in Africa • View topic - Faulty Wabco Vacuum pumps (http://landyonline.co.za/landyforum/viewtopic.php?f=6&t=2781)

300 Tdi vacuum pump failures - SA 4x4 Community Forum (http://www.4x4community.co.za/forum/showthread.php?p=651833)

Different types of failure but dont do a lot to instill confidence in the wabco unit.

Martyn

And guess which company makes the totally reliable pumps on the Puma?

I think I own the only Puma engined Defender that hasn't had this item replaced...maybe tomorrow?

I think that they are on their third edition within three years.

For those who don't know the Puma version is a belt driven unit.

[wagoo]

Not that style of problem, they have each gone noisy and stopped producing any vacuum. Something is failing internally, will pull this one apart (if I can work out how to get into it) any try and see what lets go.

A bit of research suggests the internal valves come adrift and get destroyed by the plunger.



Martyn

Dont know if it is still possible to buy the the non return valves for a CAV mechanical fuel pump as fitted to 2 1/4 litre LandRover engines. but I once used a pair of those to replace the Wabco valves that had fallen to bits.
Wagoo.

[vnx205]

I could have tacked this onto any one of quite a large number of 300Tdi vacuum pump threads. :p

Mine didn't leak any oil. It just stopped sucking. The first thing I noticed was a very hard brake pedal. Fortunately I had been trained by 23 years of driving a Series III LWB with no power assistance, so I managed to get home without any dramas.

After reading several threads here, I had the notion that I would order a new pump and dismantle the old one to see if I could fit new valves, bolt the cover back on and keep it as a spare.

However, it looks as if repairing the old pump is out of the question.

This is what was left of one of the valves. (Plus a little bent bit of wire that used to be a spring.)
http://www.fileden.com/files/2008/7/16/2005444/Valve2.JPG

One of the valves was still intact in the cover.
http://www.fileden.com/files/2008/7/16/2005444/Cover.JPG

What makes me think that it would be a waste of time to attempt a repair is those scores in the bore.
http://www.fileden.com/files/2008/7/16/2005444/Piston.JPG

I assume they are not made with those grooves in the bore.
http://www.fileden.com/files/2008/7/16/2005444/Scores.JPG

My guess is that what would happen if it was repaired is that a copious amount of oil would find its way past the piston and that once in that chamber, the increased pressure would pop one of those welch plugs out.

Anyone care to confirm my suspicions?

[dham]

I too have had ongoing 300tdi vac pump grief with a series of pumps lasting from less than 100 km to only a couple of thousand km. I got tired of this and have fitted an electric pump (an old Thomas i had lying around) c/w small vac tank and pressure switch in the box below the drivers seat. Had a ally plate made to blank-off the original mech pump engine take-off. Anyhow, when all done the electric pump ran continuosly on my first test drive with the pressure switch not activating in response to expected vacuum build-up. There was some vacuum in terms of brake response but clearly also a leak somewhere. Following a tip on this site, I removed the servo and, sure enough, there was a hairline fracture (hard to spot without close examination) around a lower master cylinder stud. New servo installed - and my brakes are better than they have been in ages with electric pump cutting in now periodically only and related to amount of braking done.

I suspect that similar problems might contribute to the Wabco issues - they just wear themselves out from overwork if there is even a small servo leak. I also noticed that the old servo was quite dusty on both sdes and it looked like some of that dust was making it's way to the Wabco which could not have aided it's longevity.

Anyhow, if there is a moral it is to check the servo before laying all blame at the foot of Wabco (which nevertheless do seem to have issues).

[vnx205]

All Four x 4 Spares seems to agree with you about the reason for pump failures.

Their online store includes this warning:

This is a quality Original Equipment part. Often the seal splits on the brake booster, so the brake booster must be vacuum tested to avoid warranty problems. On a Defender the brake booster often has a hairline crack where it is bolted onto the booster (on the LH side as you are looking at it) - this is the main reason why the vacuum pump fails.

Brake Vaccuum Pump suit Land Rover Discovery & Defender 300TDI - 4WD Spare Parts | Toyota | Nissan | Land Rover | Landcruiser | Patrol | Prado | Land Cruiser All 4x4 (http://shop.allfourx4.com.au/Brake-Vaccuum-Pump-suit-Land-Rover-Discovery-Defender-300TDI)

On the recommendation of a few earlier posts on this subject, I did check the servo and the plastic hose. My plastic hose is rubbed halfway through, but isn't leaking.

[wrinklearthur]

you could always get rid of it all together and buy a electric vaccum pump they are available on ebay Can you post a link?

then make the old pump an idler or get a shorter belt if that works
Your thinking of a different design motor or you have confused the power steering pump for the vacuum pump.
.

[vnx205]

Anyhow, if there is a moral it is to check the servo before laying all blame at the foot of Wabco (which nevertheless do seem to have issues).

It might be interesting to know how many of the people with pump failures, especially multiple failures, had subsequently found servo leaks such as those hairline cracks near the studs.

[rangieman]

I too have had ongoing 300tdi vac pump grief with a series of pumps lasting from less than 100 km to only a couple of thousand km. I got tired of this and have fitted an electric pump (an old Thomas i had lying around) c/w small vac tank and pressure switch in the box below the drivers seat. Had a ally plate made to blank-off the original mech pump engine take-off. Anyhow, when all done the electric pump ran continuosly on my first test drive with the pressure switch not activating in response to expected vacuum build-up. There was some vacuum in terms of brake response but clearly also a leak somewhere. Following a tip on this site, I removed the servo and, sure enough, there was a hairline fracture (hard to spot without close examination) around a lower master cylinder stud. New servo installed - and my brakes are better than they have been in ages with electric pump cutting in now periodically only and related to amount of braking done.

I suspect that similar problems might contribute to the Wabco issues - they just wear themselves out from overwork if there is even a small servo leak. I also noticed that the old servo was quite dusty on both sdes and it looked like some of that dust was making it's way to the Wabco which could not have aided it's longevity.

Anyhow, if there is a moral it is to check the servo before laying all blame at the foot of Wabco (which nevertheless do seem to have issues).
I actualy have a small source of 12v electric vacume pumps and have wondered how to hook these up so they cut in and out when vacume is low or close to low , What switch did you use and what size vacume tank is required im willing to give this ago and share the results and maybe a pump or 2 :cool:

[isuzu110]

All Four x 4 Spares seems to agree with you about the reason for pump failures.

On a Defender the brake booster often has a hairline crack where it is bolted onto the booster (on the LH side as you are looking at it) - this is the main reason why the vacuum pump fails.



Sorry, but I'm skeptical. Can anyone explain the science behind this theory ? My understanding is that the mechanical pump runs continuously off a cam lobe. It doesn't cut in and out based on the pressure.

I've had pumps fail prior to a hairline crack in the booster and post a new booster.

[vnx205]

Sorry, but I'm skeptical. Can anyone explain the science behind this theory ? My understanding is that the mechanical pump runs continuously off a cam lobe. It doesn't cut in and out based on the pressure.

I've had pumps fail prior to a hairline crack in the booster and post a new booster.
It is a mechanical pump and the piston does operate continuously, but maybe the valves don't

EDIT:I forgot that the piston is pushed out by the cam lobe but is returned by a spring, so I guess what bee utey says a couple of posts down about the reduced piston travel would be right. I still think what I said about the valves might be right.

I'm only guessing, but perhaps there is some truth in it because it is the plastic one way valves that fail. At least that is what failed on mine and I believe on some others too.

If vacuum has been established and the brakes are not used, then wouldn't it be the case that while the piston was moving up and down, the valves would not need to move or would only move a tiny amount.

If the valves are moving through their full range of movement repeatedly, then they would be subjected to a lot more stress than if they just moved a little bit occasionally.

That is just speculation. Someone with qualifications must know the answer.

[rangieman]

Sorry, but I'm skeptical. Can anyone explain the science behind this theory ? My understanding is that the mechanical pump runs continuously off a cam lobe. It doesn't cut in and out based on the pressure.

I've had pumps fail prior to a hairline crack in the booster and post a new
booster.
Well i can tell you for a fact that if you hook up a 12v vac pump to constant power it will suck the booster inside out this is why it needs to be switched on and off some how when vacuum is near low :eek: Maybe the mechanicle pumps run some sort of by pass vacuum valve only a guess :cool:

[bee utey]

Well i can tell you for a fact that if you hook up a 12v vac pump to constant power it will suck the booster inside out this is why it needs to be switched on and off some how when vacuum is near low :eek: Maybe the mechanicle pumps run some sort of by pass vacuum valve only a guess :cool:

This I gotta see. Pics??? How much difference is there between 25 ins vacuum from a decelerating V8 engine and 30 ins of pure vacuum? Not enough to damage a booster designed to have a margin of safety.

Electric vac pumps have switches to stop them running continuously. Mechanical vac pumps stop stroking full travel as its only a spring that causes the vacuum. High vacuum holds the diaphragm back. Also the valves nearly stop moving and so don't wear out as fast.

EV conversions use electric vac pumps to run boosters, read some EV forums if you want to find about fitting up electric vac pumps. Apparently some Volvo turbos ran them.

[PAT303]

I would be looking further if you are doing pumps all the time,have you checked that it's not deadheading?,it may just need a spacer. Pat

[isuzu110]

Could it be that when there's sufficient vaccuum in the circuit that the plunger is retracted from the lobe and does not make contact, hence wearing less and prolonging pump life

[vnx205]

It hasn't been an ongoing problem for me. This is the first replacement in almost 200,000km.

I hope the next one lasts as long.

I read a suggestion on one of the many posts on this subject that it was worth fitting a second gasket as a spacer between the pump and the block. Is that supposed to be a good idea in all cases or only if it is deadheading? I'm guessing that means the piston is contacting the top of the chamber.

[Bushie]

My original pump failed with a broken spring.
The extra gaskets was recommended by Karcraft when I purchased the new pump, and yes they have an interest in selling more gaskets, but at 65c (IIRC) they are not going to get rich.


Martyn

[landychris]

Good to know that I am not alone. I am about to go on to my 4th pump. Only got 53k's out of the last pump before the same old problem with lack of brakes. I have a 300 series Defender that I bought new in 1996 and it has done only 128,000ks. The original pump lasted 15 years. Now 3 pumps in two months:mad: I have lost faith in the reliability and about to have pump number 4 installed. Pump 3 failed while going down a hill:o It is hard to remain faithful to the green oval when trips have become potentially dangerous.
landychris

[rick130]

Chris, I've installed a Bearmach vac pump in place if the WABCO and so far so good, but it's only seen 10-15,000km so far.

Reports from here and the UK suggest the Bearmach version is far more reliable.
I hope so.

[87County]

I installed a cheaper indian type pump at the recommendation of karcraft - it's been fine for a recent 15000km return trip to W.A.

I had rebuilt my orig Wabco at about 160000km but the actual suction was diminishing (not noticed by me I might say) - But I did notice decreased brake pedal pressures when I installed the above item.

Karcraft & most other knnowledgeables seem to recommend at least a double thickness of gasket - I can see that fitting three may also be a good idea - limits pump stroke to save wear in pump body.

[landychris]

Pump number 4 is in, 100k's and all ok ......yeah:(
landychris

[Gigitt]

Too many pumps too late... my 4th replacement has died and I'm now looking at 12v vacuum pumps to replace it.

Sick to death of the poor quality of the Wabco units. The design is just so flawed.

3 of the pumps failed by seizing on the main piston spring and you get that loud tap tap tap sound as the loose rod is being slapped back up into the pump. Basically replaced under warranty.

Now the last one only traveled <1800km but is out of warranty.
Pump is not producing vacuum.
Pulled the top of and found that the main piston seal has failed and bits of the seal lip got caught in the one-way valve keeping it open.
Piston action is still good and free, tested the valves work correctly and holding pressure before putting the top head back on, but the piston seal is fully compromised and not able to pull a vacuum.

So looking at "SSBC 28146 Electric Vacuum Pump Kit Comp 5500"
or Thomas Thomas Industrial Diaphragm 12 Volt DC Vacuum Pump or Compressor model 107CDC20-898
or Summit Racing Part Number: SUM-760152

Will be operated by a relay and pressure switch.

Any thoughts which electric vacuum pump to get?
Anyone else done a conversion on their 300TDI ?
This will be going on a 130 Defender.

Cheers

[landychris]

Pump 4 still ok. After some research when/if pump 4 gives up I will look at the brake booster pump. I understand that a crook one can put too much stress on the vacuum pump.
landychris

[wrinklearthur]

I was blaming my 300TDi pump, but I decided to change the brake vacuum servo unit instead and by doing this the fault has now been cleared.

To find out why I had a intermittent hard pedal with poor stopping ability, I dismantled the servo to find that there is a lubricant around the servo push rod seal, this lubricant and the seal had gone hard with age and was allowing the vacuum to the diaphragm to be diminished by air being drawn past the push rod.

I haven't found a kit to refurbish these servo's yet, so if anyone knows where to find such a kit, could they record the link on here please?
.

[jboot51]

Paddocks have seal kits.
18G8951L - Seal kit for STC2878

18G8951L | Seal kit for STC2878 (http://www.paddockspares.com/18g8951l-seal-kit-for-stc2878.html)

AEU2741 - Seal kit for NRC4772

AEU2741 | Seal kit for NRC4772 (http://www.paddockspares.com/aeu2741-seal-kit-for-nrc4772.html)

[wrinklearthur]

Paddocks have seal kits.
18G8951L - Seal kit for STC2878
18G8951L | Seal kit for STC2878 (http://www.paddockspares.com/18g8951l-seal-kit-for-stc2878.html)
AEU2741 - Seal kit for NRC4772
AEU2741 | Seal kit for NRC4772 (http://www.paddockspares.com/aeu2741-seal-kit-for-nrc4772.html)

Thanks jboot51 for that link.

Those kit's don't have the diaphragm shown nor the lubricant.

The lubricant I found in my faulty servo looked to be a zinc oxide based rubber grease and the diaphragm's would need replacing occasionally as they can develop cracks.
.