Oil Spots On Driveway.... Mgb Not Guilty!

[tckcumming]

Oil spots on my driveway... checked my '69 MGB (the usual suspect)... nothing leaking . Looked under the ES300 - :o red tranny fluid leaking. Not much, just enough to notice. I removed the rubber hoses that go from the trans to the cooler in the bottom of the radiator. The longer hose is connected to a hard line about 18" long mounted to the frame below the rad, then another shorter hose goes from the hard line to the rad. This hard line is very corroded and "cheesy" looking, wet with fluid. I went to a local autoparts store, they didn't have any proper trans oil hoses, but I did find some rubber fuel line hose with an identical I.D. (3/8" or so?). Here's what is printed on the hose: 9.5mm 50psi Fuel/Emission SAE 30R7 Made in USA Goodyear . I bought 5 feet of it because I had already taken the old hoses off & needed something to replace them with (possible big mistake on a Saturday afternoon!!). When I installed it, I bypassed the old rotten hard line (just zip tied the new rubber hose alongside the old metal one), replaced the second shorter hose and started the car up. No leaks. Shifted through the gears, put it in "D" and revved the engine - AOK. Went for a drive around the block - still OK.

I was intending to make this a temporary repair, just until I could get some proper rubber hose for a transmission. But now that the job is done and everything is all neatly cleaned up and zip tied in place, I want to leave it as is. Anyone have an opinion about this? Can the fuel line hose handle the pressure in the trans line over time? I have no idea how much pressure is generated in the oil cooler lines, but I think a 50 psi-rated hose should be able to handle it - do you think??

I'm also considering adding an external transmission filter, plumbing it into the hoses I just replaced should be a snap. Where can I get an external filter?

tck...

[ArmyofOne]

Oil spots on my driveway... checked my '69 MGB (the usual suspect)... nothing leaking . Looked under the ES300 -  :o  red tranny fluid leaking. Not much, just enough to notice. I removed the rubber hoses that go from the trans to the cooler in the bottom of the radiator. The longer hose is connected to a hard line about 18" long mounted to the frame below the rad, then another shorter hose goes from the hard line to the rad. This hard line is very corroded and "cheesy" looking, wet with fluid. I went to a local autoparts store, they didn't have any proper trans oil hoses, but I did find some rubber fuel line hose with an identical I.D. (3/8" or so?). Here's what is printed on the hose: 9.5mm  50psi   Fuel/Emission  SAE 30R7  Made in USA  Goodyear . I bought 5 feet of it because I had already taken the old hoses off & needed something to replace them with (possible big mistake on a Saturday afternoon!!). When I installed it, I bypassed the old rotten hard line (just zip tied the new rubber hose alongside the old metal one), replaced the second shorter hose and started the car up. No leaks. Shifted through the gears, put it in "D" and revved the engine - AOK. Went for a drive around the block - still OK.

I was intending to make this a temporary repair, just until I could get some proper rubber hose for a transmission. But now that the job is done and everything is all neatly cleaned up and zip tied in place, I want to leave it as is. Anyone have an opinion about this? Can the fuel line hose handle the pressure in the trans line over time? I have no idea how much pressure is generated in the oil cooler lines, but I think a 50 psi-rated hose should be able to handle it - do you think??

I'm also considering adding an external transmission filter, plumbing it into the hoses I just replaced should be a snap. Where can I get an external filter?

tck...

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I think the fuel line is a fine idea. even if you have to replace it 3 or four times a year, its cheaper and easier than replacing that steel hose. those lines however, are pressurized for a reason. An ATX (Automatic Transaxle) works off of pressure, same as a transmission in a RWD car. Im sure you know this. now by putting a rubber hose in place of a steel one, that rubber hose may flex under pressure, therefore changing the PSI that the tranny recieves.

however, you said it is working OK, i would give it a week or so. DONT unziptie it from the hardline, that is the only thing keeping the hose from flexing and affecting the pressure.

im sure you understand the dynamics of a hydraulic system...the farther you pump the fluid, the less pressure it transmits, or rather, the more pressureis required to make whatever it is you are trying to make work...work.

I hope that makes sense.

[Toysrme]

Oil spots on my driveway... checked my '69 MGB (the usual suspect)... nothing leaking

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ahhhhhhhhhhhhhhhhhhhhhhhhhhhhh

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I'm not sure what the pressure to the cooler is, line pressure in the transmission can exceed 200psi. (Cooler pressure is way under that tho, don't worry). I just used 5/16" high temp fuel/oil hose on my aux. trans cooler & turbo return lines I bought off ebay. I still ahve tons of the stuff laying around.

Most common oil hose has a 250psi burst rating, 257*F temp. Real good hose get's up to 270-290*F at 275-300psi. You need to kill off the fuel hose, that's going to be a bad idea over time. Get some oil hose.

Zipties works well for mounting. Hose clamps get used for mounting a lot, but that is a BAD idea! They cut into the transmission line as it flexes. That would be a mess!

If you're going to add a filter, add an aux cooler after the main one!!! Just go buy an oil cooler out of a junkyard for like $5-10 and mount it. The $40 stacked plate coolers are great, but eh... If you're retaining the stock cooler, just some old cheap crap that's stock on another car will work fine!

And please use good hoseclamps to clamp, that can't be said enough. ;)

[tckcumming]

Im sure you know this. now by putting a rubber hose in place of a steel one, that rubber hose may flex under pressure, therefore changing the PSI that the tranny recieves

You are right, a kink or bend in the hose would create problems.

The hard line is connected with rubber hoses on both ends - one end to the line coming from the trans, the other end to the trans cooler. So I figure that all I've really done is lengthen the rubber hoses that were already there. Instead of 2 rubber hoses with a steel line in the middle, I now have only 1 (longer) rubber hose. The overall length from trans to cooler is the same as before, it's just that now there is no steel line in between. I was really careful not to let the hose kink or twist - that's why I ziptied it to the steel line, so it couldn't flex or kink.

I'm not sure what the pressure to the cooler is, line pressure in the transmission can exceed 200psi. (Cooler pressure is way under that tho, don't worry).

Most common oil hose has a 250psi burst rating, 257*F temp. Real good hose get's up to 270-290*F at 275-300psi. You need to kill off the fuel hose, that's going to be a bad idea over time. Get some oil hose.

Zipties works well for mounting. Hose clamps get used for mounting a lot, but that is a BAD idea! They cut into the transmission line as it flexes. That would be a mess!

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I figured that the trans cooler can't be anywhere near line pressure - 200 psi would surely blow something out. The coolant in the rad is at about 17 psi. Even if the trans cooler is double that I should be OK with a 50 psi hose. I guess I'll find out.

And please use good hoseclamps to clamp, that can't be said enough. ;)

I use those solid metal clamps - the ones with a little captive square nut and a bolt. I don't like the usual slotted-gear type as they do seem to cut into the hose & cause problems occasionally.

To be honest, this concerns me even more...

Oil spots on my driveway... checked my '69 MGB (the usual suspect)... nothing leaking

When the MGB isn't leaking, it means that either all the fluids have already leaked out or something is about to go BANG.

Think I'll go have another look...

tck...

[SKperformance]

I agree the fuel line is fine.

The pressures of the cooler is 25-35 psi ,so it is very low which is why no one even makes tranny pressure gauges.

I would get a new rad ,you need the heat to circulate the fluid properly in the tranny.

It is not a good idea to keep running the car without so sort of initial heat to lower the viscosity of the tranny fluid.

I know it sounds backwards to need heat when it has a cooler but it is really just a heat exchanger working in both directions to give and take heat.

[tckcumming]

I agree the fuel line is fine.

The pressures of the cooler is 25-35 psi ,so it is very low which is why no one even makes tranny pressure gauges.

←

Thanks, skperformance, that makes me feel better.

I would get a new rad ,you need the heat to circulate the fluid properly in the tranny.

It is not a good idea to keep running the car without so sort of initial heat to lower the viscosity of the tranny fluid.

I know it sounds backwards to need heat when it has a cooler but it is really just a heat exchanger working in both directions to give and take heat.

The cooler is still hooked up - I just bypassed the steel line. Like this...

rad_diag.bmp

Do you like my sophisticated CAD drawing??

BTW - I do need a new rad - I've just been putting it off - more important things to spend my $$ on...

tck...

ps. - found a small hydraulic leak from clutch slave on MGB - great relief - it's very disconcerting when the MG has no leaks... the universe is in balance again...

[SKperformance]

I thought it was the line leading onto the rad that you bypassed.

So if it still goes in the rad then you are fine running it that way.

[Toysrme]

That is just a really bad idea. PM me, I will send you some oil hose if you promise to put it on ASAP.

:) The MGB is leaking!¡!