AIR Pump prototype failure
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
AIR Pump prototype failure
...Those who may remember my posting a few mths ago about my AIR pump that I had re-engineered as a freewheeling pulley;
Was on the highway this morning, when I suddenly noticed the steering had lost it's directness...Temp started to climb accordingly, so I figured the serpentine belt had broken. Luckily I was dropping in on a mate who lived a mile away. Steering was heavy as hell. When I pulled up; radiator was boiling from overflow.
To my amazement, the belt was fine, but sitting in the engine bay, along with the PULLEY from the re-engineered AIR pump that I had converted to a free wheeler about 600miles ago!!!
We pulled it down and the 18mm THICK solid steel shaft had been milled down to a mere few mm's and sheared! PILE of graphite looking powder found INSIDE the case! Cause is not known at this stage, until I get the bits back to engineer on Monday. The BIG front and rear bearings SEEM ok and not ceased, so it's a weird one! I'm figuring end play but what acted as a dremel on the shaft??
I'll keep those interested posted on the findings...
:confused:
[Modified by smacko, 10:25 PM 11/20/2003]
Was on the highway this morning, when I suddenly noticed the steering had lost it's directness...Temp started to climb accordingly, so I figured the serpentine belt had broken. Luckily I was dropping in on a mate who lived a mile away. Steering was heavy as hell. When I pulled up; radiator was boiling from overflow.
To my amazement, the belt was fine, but sitting in the engine bay, along with the PULLEY from the re-engineered AIR pump that I had converted to a free wheeler about 600miles ago!!!
We pulled it down and the 18mm THICK solid steel shaft had been milled down to a mere few mm's and sheared! PILE of graphite looking powder found INSIDE the case! Cause is not known at this stage, until I get the bits back to engineer on Monday. The BIG front and rear bearings SEEM ok and not ceased, so it's a weird one! I'm figuring end play but what acted as a dremel on the shaft??
I'll keep those interested posted on the findings...
:confused:
[Modified by smacko, 10:25 PM 11/20/2003]
Safety Car
Joined: Sep 2003
Posts: 4,504
Likes: 0
From: Charleston SC
Re: AIR Pump prototype failure (smacko)
This might be completely rediculous but maybe the bearing binds up only when it's hot. Havig air constantly pumped through the housing would keep it cool but that's not happening any more.
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (rkessel)
I have considered this also, but as the new bearing sits in a 1/2" thick alloy plate, this SHOULD be enough in itself to dissipate heat.
After looking at it today, the engineer has no real explaination either for it. But I did say that I'd pay the difference if they use case hardened steel on this new shaft...
After looking at it today, the engineer has no real explaination either for it. But I did say that I'd pay the difference if they use case hardened steel on this new shaft...
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Melting Slicks
Joined: Nov 2003
Posts: 3,375
Likes: 1
From: Northern CA
Re: AIR Pump prototype failure (smacko)
Is it possible that whatever was holding the shaft in place fore/aft failed and let the shaft slide forward enough that it was only supported by the front bearing?
That could have let the shaft wobble a bit in the front bearing and the much harder bearing could have brinelled the relatively soft shaft until is sloughed of bazillions of itty bitty pieces. :confused:
That could have let the shaft wobble a bit in the front bearing and the much harder bearing could have brinelled the relatively soft shaft until is sloughed of bazillions of itty bitty pieces. :confused:
Burning Brakes
Joined: May 2000
Posts: 958
Likes: 0
From: Brisbane, Australia 1985 Coupe
Re: AIR Pump prototype failure (JAKE)
Excellent link Jake! Thanks.
Steve, just get rid of the whole thing! rkessel made a good point which I didn't even think of before. There wouldn't be much grease in the bearing to compensate for the high speed it is spinning at.
Sorry you couldn't make it on Sunday.
:cheers:
Steve, just get rid of the whole thing! rkessel made a good point which I didn't even think of before. There wouldn't be much grease in the bearing to compensate for the high speed it is spinning at.
Sorry you couldn't make it on Sunday.
:cheers:
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (xs650)
Mate, I think you've hit the nail on the head!
There IS nothing apart from a tight fit, to stop the shaft moving to or fro!!!
Will ring the engineers NOW.
Many thanks, I've been racking my brain over this! :cheers:
There IS nothing apart from a tight fit, to stop the shaft moving to or fro!!!
Will ring the engineers NOW.
Many thanks, I've been racking my brain over this! :cheers:
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Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (Chris O')
Chris, I think xs650's got the cause...
I'm VERY dissapointed that the engineers didn't think of this; they HAVE been good in the past. Will see what they say. Maybe they can make me up the eliminator instead of wasting more money on refurbishing the pump...
I'm bloody disappointed too about Sunday, BUT who knows; it may be a blessing in disguise
I'm VERY dissapointed that the engineers didn't think of this; they HAVE been good in the past. Will see what they say. Maybe they can make me up the eliminator instead of wasting more money on refurbishing the pump...
I'm bloody disappointed too about Sunday, BUT who knows; it may be a blessing in disguise
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (Trog)
STOP THE PRESS!
Just spoke to the engineer; I'd forgotten, the shaft DOES have a shoulder behind both bearings to stop end play, so the theory above isn't applicable afterall. What HE has come up with, is that as mine was the first one they made, it's possible that if there was a tho clearance between the shaft and inner bearing shell, it could have had enough movement to slowly wear it down and given the bearings still seem fine and are 12 x the hardness of the original mild steel shaft AND the wear only takes place at the same thickness of the bearing, this must have been the case.
The second one he made for someone else, doesn't have this clearance.
As you said Trog, it is possible then that the shaft was spinning without the bearing.
So he's going ahead and redoing it with case hardened axle steel and new bearings and a grub screw on the front as an added precaution.
The sealed bearings show NO sign of wear at all.
Just spoke to the engineer; I'd forgotten, the shaft DOES have a shoulder behind both bearings to stop end play, so the theory above isn't applicable afterall. What HE has come up with, is that as mine was the first one they made, it's possible that if there was a tho clearance between the shaft and inner bearing shell, it could have had enough movement to slowly wear it down and given the bearings still seem fine and are 12 x the hardness of the original mild steel shaft AND the wear only takes place at the same thickness of the bearing, this must have been the case.
The second one he made for someone else, doesn't have this clearance.
As you said Trog, it is possible then that the shaft was spinning without the bearing.
So he's going ahead and redoing it with case hardened axle steel and new bearings and a grub screw on the front as an added precaution.
The sealed bearings show NO sign of wear at all.
Burning Brakes
Joined: Dec 2002
Posts: 1,199
Likes: 4
From: Cairns Australia
Re: AIR Pump prototype failure (smacko)
I'm the other person that had their pump re-engineered at the same place.
Smacko emailed me yesterday to say that after 600kms his pump had failed - My pulley had already fallen off once because of the lack of a grub screw so, due to the delays in returning it etc, I only re-fitted it last Thursday and had only done about 80kms since the pump was turned into a free wheeler.
I thought I had some time to find out what the problem was, but.......
Unfortunately it failed this morning. I blame Smacko, he must have jinxed it (although he lives 2000kms away)
My bearings are almost siezed. Considering it's doing no work just freewheeling around, I'm suprised.
Damm you , Smacko...........
Smacko emailed me yesterday to say that after 600kms his pump had failed - My pulley had already fallen off once because of the lack of a grub screw so, due to the delays in returning it etc, I only re-fitted it last Thursday and had only done about 80kms since the pump was turned into a free wheeler.
I thought I had some time to find out what the problem was, but.......
Unfortunately it failed this morning. I blame Smacko, he must have jinxed it (although he lives 2000kms away)
My bearings are almost siezed. Considering it's doing no work just freewheeling around, I'm suprised.
Damm you , Smacko...........
Burning Brakes
Joined: Dec 2002
Posts: 1,199
Likes: 4
From: Cairns Australia
Re: AIR Pump prototype failure (Stingraynut)
Quote" Damm you Smacko".....he he he
Only kidding, of course, but you gotta blame someone and when I rang the engineer he didn't want to know so........
(I also blame the weather forcasters when there's a drought, obviously - it;s THEIR fault, they know about these things)
S'nut
Only kidding, of course, but you gotta blame someone and when I rang the engineer he didn't want to know so........
(I also blame the weather forcasters when there's a drought, obviously - it;s THEIR fault, they know about these things)
S'nut
Pro
Joined: Dec 2002
Posts: 522
Likes: 3
From: Rolling Meadows IL
Re: AIR Pump prototype failure (Stingraynut)
There is an easer way and it won’t cost you a penny. Take the pump apart and just crack the blades and holders out of it then reuse the empty “drum” shaft with the original bearings.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: AIR Pump prototype failure (dave_85)
My guess is the bearing had a clearance fit on the shaft, and the shaft was spinning in the bearing. Check the bearing's ID surface for wear. What is that shaft made of? Is it heat treated/shotpeened/hardened in any way?
EDIT
oh, nevermind, looks like you've got it all figured out! Geez, I wish I had my own personal engineer! :lol:
[Modified by CentralCoaster, 3:03 PM 11/18/2003]
EDIT
oh, nevermind, looks like you've got it all figured out! Geez, I wish I had my own personal engineer! :lol:
[Modified by CentralCoaster, 3:03 PM 11/18/2003]
Burning Brakes
Joined: Dec 2002
Posts: 1,199
Likes: 4
From: Cairns Australia
Re: AIR Pump prototype failure (dave_85)
Thanks Dave_85, my pump had a bad back bearing - I posted a while back http://forums.corvetteforum.com/zerothread?id=606732
So that wasn't an option for me, not sure about Smacko but I think he too had a noisy bearing.
I've just taken mine apart and found that the front bearing has almost seized, can't get it off the shaft yet, may need a press. There appears to be a hard green substance which I think is some kind of loctite all around the join of the shaft to the front of the bearing. I also found some wet green paste on the end of the shaft where there is no contact. Maybe the loctite has seeped into the bearing - I'd only done about 50 miles with this new bearing.
I'm going to take it to a local enginering shop and get them to press the bearing off the shaft and give me an opinion about what's happening.
S'nut
So that wasn't an option for me, not sure about Smacko but I think he too had a noisy bearing.
I've just taken mine apart and found that the front bearing has almost seized, can't get it off the shaft yet, may need a press. There appears to be a hard green substance which I think is some kind of loctite all around the join of the shaft to the front of the bearing. I also found some wet green paste on the end of the shaft where there is no contact. Maybe the loctite has seeped into the bearing - I'd only done about 50 miles with this new bearing.
I'm going to take it to a local enginering shop and get them to press the bearing off the shaft and give me an opinion about what's happening.
S'nut
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (Stingraynut)
I have JUST got home (aprox 11pm) AFTER working a 12hr shift (as usual)
Drove up to where my mate has my vette, with pump.
went to put pulley on...
...
...
...
WONT kissING FIT BECAUSE JOH DIDNT ADD 3mm TO FRONT AS PER CLEAR INSTRUCTIONS, THREE TIMES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!
(This was so that pulley was in alignment with other pulleys, as I now knew how much further front of assembly needed to protrude...BACK to having to take it BACK AGAIN SOMETIME as I have to work next couple of days.(Although he said he'd charge me for any future work on it, after graciously not charging me today to fix whatever went wrong!!)
He thought maybe my shaft (or the pumps anyway) was too loose in bearing (at front). NEW shaft is axle steel, but doesn't do me any good at the moment with pulley rubbing on bracket bolts!!! :mad
Drove up to where my mate has my vette, with pump.
went to put pulley on...
...
...
...
WONT kissING FIT BECAUSE JOH DIDNT ADD 3mm TO FRONT AS PER CLEAR INSTRUCTIONS, THREE TIMES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!
(This was so that pulley was in alignment with other pulleys, as I now knew how much further front of assembly needed to protrude...BACK to having to take it BACK AGAIN SOMETIME as I have to work next couple of days.(Although he said he'd charge me for any future work on it, after graciously not charging me today to fix whatever went wrong!!)
He thought maybe my shaft (or the pumps anyway) was too loose in bearing (at front). NEW shaft is axle steel, but doesn't do me any good at the moment with pulley rubbing on bracket bolts!!! :mad
Burning Brakes
Joined: May 2000
Posts: 958
Likes: 0
From: Brisbane, Australia 1985 Coupe
Re: AIR Pump prototype failure (smacko)
If you make me an eliminator bracket from Jakes link, I'll give you my pump! ;) I want to get rid of mine asap to clean the engine bay up.
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (Chris O')
If you make me an eliminator bracket from Jakes link, I'll give you my pump! ;) I want to get rid of mine asap to clean the engine bay up.
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (continued)
Well, I was SO stressed about my stupid PUMP all night, I decided to get up
even earlier this morning and TAKE the damned thing up there before work
Arrived at the engineers gate at 7.30, JUST as two of the blokes (Not sure if they're apprentices or what) were opening, I gave the pump to them, along with a to the point letter expressing I think my huge disappointment and instructions to FIX IT PROPERLY as I'd have someone collect it this avo...2 hrs later got a call saying it was READY. One of the other blokes had done it, made (ANOTHER) new hardened steel shaft and done it all.
Have had a good look at it; it has the aprox extra length I need AND spins the best out of the 3 versions, so here's hoping.
I AM feeling more positive all round now...Maybe if the one who did
VERSION 3 IS an apprentice, he did a better job by virtue of maintaining
exactness, rather than complacency, which can happen I guess...THE
SORCERER'S APPRENTICE! :smash:
even earlier this morning and TAKE the damned thing up there before work
Arrived at the engineers gate at 7.30, JUST as two of the blokes (Not sure if they're apprentices or what) were opening, I gave the pump to them, along with a to the point letter expressing I think my huge disappointment and instructions to FIX IT PROPERLY as I'd have someone collect it this avo...2 hrs later got a call saying it was READY. One of the other blokes had done it, made (ANOTHER) new hardened steel shaft and done it all.
Have had a good look at it; it has the aprox extra length I need AND spins the best out of the 3 versions, so here's hoping.
I AM feeling more positive all round now...Maybe if the one who did
VERSION 3 IS an apprentice, he did a better job by virtue of maintaining
exactness, rather than complacency, which can happen I guess...THE
SORCERER'S APPRENTICE! :smash:
Thread Starter
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: AIR Pump prototype failure (smacko)
I not long ago arrived home with my Corvette FOLLOWING ME on a TILT TRAY after the re-re-engineered pump broke YET AGAIN! Not as sore as the 'Engineer' will be when he finds out why I rock up with a 44gallon tub of margarine and the broken pump and say to him "Bend over Lovie!"
At least I got 10miles out of this one...worth ALL the stuffing around, wouldn't you agree??
Was stranded on a dark stretch of road only 3 Kilometers from home!!! And had to call in sick at work. Fan belt has this time shredded itself well and truly; looks like rear bearing had nothing stopping it from working its way backwards and grinding the pulley into a front bolt. SHAFT is still intact this time tho :mad
At least I got 10miles out of this one...worth ALL the stuffing around, wouldn't you agree??
Was stranded on a dark stretch of road only 3 Kilometers from home!!! And had to call in sick at work. Fan belt has this time shredded itself well and truly; looks like rear bearing had nothing stopping it from working its way backwards and grinding the pulley into a front bolt. SHAFT is still intact this time tho :mad