Air Con Pump..Time to talk seriously.

[frank rabbets]

I took my air con pump off to strip it to see whether or not low oil might have damaged it and to fit a new shaft seal as a precaution. The air con was working fine btw.

The pump is scrap but I don't think caused by low oil. Two of the reed valves have snapped off and one of the broken pieces has managed to go round the pump. One of the pistons and its bore are badly damaged and one of the thrust races has fallen to bits.



The picture shows the affected valve body opened up like an oyster just as it came apart. The LH shows where 2 of the reeds have snapped off and are missing. The RH shows one broken off reed but the other is gone. How it got through the hole, unlike the other retained one, is a mystery.

Do these feed valves break after a while through metal fatigue?

I'd like advice on which of the following to do.

1. Buy a new pattern pump.
2. Buy a new Toyota pump.
3. Build a pump out of parts but if metal fatigue is a cause of failure it may not last long.

 

[frank rabbets]

Just phoned Toyota and they quoted £323 exchange pt no 88320-60630

 

[GuyB]

I recently paid £300 for a reconditioned Toyota pump so 323 sounds good...

Sent from my HTC One_M8 using Tapatalk

 

[StarCruiser]

I'm getting a price (when he gets round to it) from my Fridge engineer mate. Should be a Denso compressor I believe though I haven't looked yet.

Broken reed valves can indicate that it could have gone hydraulic at some point. That could be oil or liquid refrigerant but on AC it is rare for liquid to get back I would have thought. This usually occurs on lower temperature stuff where the evaporator ices up and it starts frosting back to the compressor, unlikely to happen on AC. So, metal fatigue or too much oil. The reeds could be available as a spare or in a service kit.

I can ask if he's come across this.

 

[Jon Wildsmith]

Just phoned Toyota and they quoted £323 exchange pt no 88320-60630

Inc or ex vat? Doesn't seem a bad price if it's inc. A chap down the road from me said he put a second hand pump off a Kia on his 80, same pump just a different block on the top where the pipes connect. Don't think older Kia's lasted very well so should be some low mileage Kia's in breakers yards with good aircon pumps on?

 

[frank rabbets]

I think that was ex VAT. I did not get a full quote as was not talking to the man who usually gives me a discount.

SC if you bend the reeds one way they come up against a shaped plate which presumably stops overbending and breakage. There's no overbending on the shaped plate. It's impossible to bend the reed the other way as it is lying flat on the valve plate. There is a hole in the plate underneath but it would take immense pressure for the reed to bend into the hole and the way they are broken is directly where the flexing in normal use takes place so I think it must just be metal fatigue. Whatever happens I shall open up the filter/drier to make sure the filter has not ruptured which can happen when thousands of fine metal particles block it. When the filter ruptures the particles are forced through the system and a major clean is presumably required.

 

[Dave2000]

I have only seen valve bodies look like that after a compressor was filled with too much oil and not turned by hand about 20 times to disperse it from the chambers simply known as hydraulic damage, or from debris left in the system from a previous compressor failure, normally caused by someone bypassing the pressure switch and forcing the compressor to run dry.

Maintained correctly the Denso pumps will run forever IME, and yes your system is going be in need of a good strip and clean I am afraid Frank.

Regards

Dave

 

[Dave2000]

Inc or ex vat? Doesn't seem a bad price if it's inc. A chap down the road from me said he put a second hand pump off a Kia on his 80, same pump just a different block on the top where the pipes connect. Don't think older Kia's lasted very well so should be some low mileage Kia's in breakers yards with good aircon pumps on?

I have fitted a Kia pump on an 80 in fact it is still running around Spain and I believe working fine but, it was not a straight bolt on, I had 4 mounting blocks made up at a local engineering shop, the unit IIRC was either too close to the engine or out of line, I cannot remember but, I do recall when charging it with the refrigerant it locked on engagement (hydraulic), some refrigerant was pulled out and then tried again and it run and AFAIK is still running. The conclusion was the KIA unit whilst looking close to the 80's physical size the internal chambers were way smaller. We are seeing the smaller compressors a lot now as AC is now fitted pretty much as standard even on the little 3 cylinder FIAT's, the small compressors along with the new R1234yf style refrigerant being used (R134 is going the same way as R12) will mean more shop equipment purchases being made and AC repair prices going up.

regards

Dave

 

[frank rabbets]

Hi Dave, I bought the car 3 years old with 30K on the clock and full history so I expect the compressor is original. The switch has never been bypassed. The car now has 149K on it and the A/C is on 90% of the time. Hydraulic locking might have occurred but I can't see how the reeds can be overstressed as they are held against a flat plate on one side and on the other side there is a strong shaped plate limiting the reeds' travel and this has not been bent. In view of this do you still think it might have been a hydraulic fault ?

Dave if the filter/drier is not ruptured presumably I need only clean out the pipes and condenser which are between the pump and filter/drier as the dbries will not have gone beyond the filter ? Obviously I'll be putting in a new filter/drier.

Thanks for everyones help on this one!

 

[StarCruiser]

I'm beginning to wonder what I am going to find in mine!![emoji20]

 

[Dave2000]

Hi Dave, I bought the car 3 years old with 30K on the clock and full history so I expect the compressor is original. The switch has never been bypassed. The car now has 149K on it and the A/C is on 90% of the time. Hydraulic locking might have occurred but I can't see how the reeds can be overstressed as they are held against a flat plate on one side and on the other side there is a strong shaped plate limiting the reeds' travel and this has not been bent. In view of this do you still think it might have been a hydraulic fault ?

Dave if the filter/drier is not ruptured presumably I need only clean out the pipes and condenser which are between the pump and filter/drier as the dbries will not have gone beyond the filter ? Obviously I'll be putting in a new filter/drier. !

Sometimes you can get reeds vibrating like a tuning fork, this can cause them to work harden and break off, what I find strange is that they have disappeared, they normally get jammed in the valve opening, odd one this Frank? Your quote 'the air con was working fine btw' does give the 'if it ain' broke don't fix it' saying a little credibility.

Cleaning and a new dryer should be sufficient frank, remove the condenser and put a solvent in it, 'swoosh' (what a great word) it about a few times rinse and repeat, any tiny particles of debris will be stuck in the condenser and lead pipe, the oil making it very sticky in there so don't take any short cut's here.

regards

Dave

 

[StarCruiser]

Would brake cleaner be a suitable 'solvent' do you think Dave?

 

[frank rabbets]

Yes it was working Dave, not even noisy, but out of interest like I say they are easy to strip and I wanted to check for possible lack of oil. First I turned the pump over on the car by hand and found it had a stiff spot every revolution. Then I noticed there was a lot of end play in the shaft. Hello Hello Hello I thought.

Dave to double check with you I don't have to strip the evaporator if the filter is not burst?

The oil in the compressor was COMPLETELY clean so I guess the filter was doing it's job and just returning clean oil.

SC if yours is seized it will most likely be scrap. I have taken a seized one apart. The pistons are coated in PTFE which gets scraped off and the ally bores get ruined. The thrust races being under too much stress break apart and the waffle plate on the spindle gets scuffed. That's the bad news...............There isn't any good .

 

[frank rabbets]

I'm pretty sure I've found the cause of my pump failure. The pulley bearing was loose on the nose of the pump. The vibration has caused wear on the nose and with the application of constant force from the tapered c clip the bearing has worn itself towards the pump. This has caused that the clutch air gap to increase. This means that when the A/C clutch worked it put too much pressure on the rear A/C bearing which collapsed.

You can see the stretched bearing cage. One of the rollers has go into a cylinder through the inlet reed and out through the exhaust. The piston is damaged and also the exhaust reed safety/retaining plate is bent.

The rollers are parallel in form and run on a flat surface but are forced into a circular motion by the cage. Any excessive stress means they try harder to run in a straight line and break the cage. Later pumps have larger diameter rollers to act more like bicycle wheels rather than rollers.

 

[Dave2000]

Brake cleaner fine but really go at it Frank, evaporator should be fine if the filter is on one piece. The bearing failure is rare on this model Frank, can't remember the last one seen like that?

regards

Dave

 

[Dave2000]

BTW Frank, go for the new Toyota unit, OE stuff will have met more stringent post manufacture tests, more often than not made on the same production line, the best go to OE the rest get spread out to other customers, whoever pays the best money gets the next best components or the 'near enough's' the rest get rejected stripped and rebuilt or sold to someone who has no intention of meeting warranty commitments.

regards

Dave

 

[frank rabbets]

Thanks Dave the pulley had gone back such a long way it was rubbing on the coil on the compressor !!

 

[frank rabbets]

I removed the condenser and drier after the compressor. I have only retrieved a total of 25 cc oil. I assume the evaporator might have some oil in, say 10 cc, so that's an optimistic total of 35 cc in a system which should have 200 cc (7 ounces).

Shall I add the whole 200 cc assuming my new compressor has none ? Do I add a bit in each component ?

I cut the bottom of my drier and fortunately the filter had not burst and no metal fragments will have gone to the evaporator.



The top of the filter trapped metal fragments but only a few very small ones.



I cleaned out the evaporator with some very thin degreaser and passed the contents through a strainer but found no fragments. The evaporator holds 700 cc. I lay it horizontally after draining and heated it with a hair drier. It suddenly got hot after several minutes indicating that all the fluid inside had gone.

I don't have faith in reconditioned compressors as Denso do not supply any parts other than to car makers. I've ordered a new Toyota one at £349 incl VAT but exchange. I don't know what they do with old ones. Having stripped several seized ones even the housings are damaged beyond repair. Some sort of mild con I think.

The pictures are of a Toyota drier. I think what happens when a genuine filter blocks is that the pressure builds up on the inside and starves the outlet to the evaporator thus activating the cut off switch. It could be that a cheaper filter blocks and bursts sending metal fragments into the evaporator causing a real nightmare.

Don't believe it when your air con man tells you he is adding oil. It might not be true by intent, ignorance or mistake. Add all the oil yourself and just regas. Does all this sound OK.

 

[Dave2000]

The new unit will come with the oil already in it Frank but, get a clean measuring jug and pour it all out and measure it, it should come to 7oz, put the oil back in ensuring the total equals the aforementioned 7oz, cycle it by hand a few times, then after refitting go to the AC workshop and tell him what you have done, he should vac the system and then refill, if you advise it has a new compressor with 7oz of oil he will pull the vacuum to boil out the moisture probably around 30 - 40 minutes?

After that he will refill with R134, the oil will distribute slowly around the system within the refrigerant, of course the compressor has the oil first as this the major moving component.

regards

Dave

 

[Dave2000]

Meant to add, the oil you put in will to all intents and purposes stay in the compressor, some will come out but it will be minimal.

regards

Dave