MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Oil pressure Gauge Stuck

Oil pressure gauge is stuck at 45 lbs. Tapping on the glass did nothing. Gauge has been sitting for 40 plus years. I did clean the line out prior to assembly but did nothing to the gauge itself.

Suggestions would be greatly appreciated.


Dan
Dan Nordstrom

A spray of very light oil (WD40 or similar) into the casing fixed mine.
Dave H
Dave Hill

Most of the gauge works like a watch. If a watch doesn't work it has to be cleaned and to be oiled with oil that watchmaker uses.
Bela

Thank you gentlemen. Sounds like I'll have to pull the gauge. Small fingers required.

Dan
Dan Nordstrom

The gauge consists of an sealed chamber in a roundish shape. When pressure is applied, the chamber wants to straighten out which drives a gear attached to the needle. Chances are the gear has jammed. Probably a bit of cleaning will straighten things out.
Lew3

From memory, harking back to my old instrument fitters days in the 60's I believe it's called a Bourdon tube. A really simple instrument with just a hairspring, gear & pointer & I agree it just needs a good clean. Cheers
Peter TD 5801
P Hehir

Confirm there is not a dampening "snubber" fitted in the inlet port, as these have a very small orifice they can become blocked. Usually on Bourdon gauges they are threaded into the port and can be removed for cleaning.

Graeme
G Evans

Thanks gents,

All is well now. A little light weight lube and all seems good.

Thanks again, Dan
Dan Nordstrom

Dan -

Did you disassemble case of the oil pressure gauge? If so, how? (talking about the gauge, not the cluster) I tried to lube the oil pressure gauge in my TF last year but couldn't see anything or get to anything to oil. So it still sticks. Tapping on the back of the gauge resets it.

Lonnie
TF7211
LM Cook

Lonnie,

I removed the gauge (only) from the panel with my "little fingers" lol and left it assembled. I sprayed a little LPS #2 in the hole and lightly worked the needle back and forth. I then VERY lightly blew it with compressed air and let it rest for about an hour. Before I put it back, I hooked it up outside of the car for a test. Upon confirmation I returned it to its respectful location. All is well.


Dan
Dan Nordstrom

Thanks Dan

I hope that I will have time to remove and lube my gauge while my gearbox is out. A lot more room to maneuver without the gearbox.

Lonnie
TF7211
LM Cook

Success!

Thanks everyone for your info. I put a few "micro drops" of lubricant on the pivot pin and spring, and I also shot some WD40 into the fitting on the back of the gauge to flush out the Bourdon tube. It reports accurate pressure for the first time since I bought the car two years ago.

Lonnie
TF7211
LM Cook

It is interesting to read this thread since the oil pressure gauge on my TF-1500 just yesterday started acting "sticky". It is taking about 2 minutes to bleed down to 0 after shutoff, but it jumps right up to 50 psi when started and stays between 45-50 while running.
Jack Long

Jack -

Don't know if it helped ... in addition to clean and lube, I added a leather washer between the oil pipe and the gauge. Mine was missing. Perhaps the flange on the pipe was covering the inlet on the gauge(?)

The one shown on the Moss dashboard diagram is:
Moss #435-516 "WASHER, leather, pipe to oil gauge"

I had ordered the wrong one that was the same O.D. but had a larger I.D. so I used it. Moss #435-515

Lonnie
TF7211
LM Cook

Gentlemen,
There is something else here that shouldn't be overlooked as well.

If the gauge cannot drop (return to zero) immediately you could easily toast a motor should there be a sudden drop in oil pressure. (the gauge is reading pressure, but there is none) I am more concerned about the return action than I am about the up side.


A gauge that does not return freely isn't much better than no gauge at all.

Dan



Dan Nordstrom

My gauge (combined oil/water) was dysfunctional after the workshop had replaced the cabling behind the dashboard.
It basically jumped between 0 and max only after wiggling the pipe and sas stuck otherwise.
The whole pipe was under significant stress, pressing into the instrument. My suspicion is that this stress prevented free movement of the needle. WD40 sprayed into the instrument did not help much (btw - where did you guys find a hole to spray into the instrument - I had to carefully pull the face forward with a tweezer to find an opening...)
I took the bracket off and let the instrument push free out of the dash, and the needle moved again.
You coudl see that wigling the pipe actually transfers directly to the center of the needle.
After that, I bent the pipe step by step until the instrument was sitting largely stress free in its final position. Now it works ok.
Seems the pipe must not be under stress to prevent blocking the mechanism.

Does anyone know a source for a diagram or picture of the inside of the combined meter ?

Another question, but IŽll post that extra
Rgds, Mike



Mike Fritsch

Mike,

Do you have a TD or TF? The TF gauges are all stand alone units and can be removed individually. They also have a very small opening that allows for a small tube (WD40 or LPS#2) to enter.
I am not familiar with the TD so I cannot offer a suggestion. Although what you have done sounds like the fix you needed.

Dan

Dan Nordstrom

I have a TD and the combined oil/water gauge.
There are various screw heads visible on the back part of the casing, but I did not want to remove any of them without knowing what they hold on the inside..
Does anyone have a source of photos or drawings of an open instrument?
Rgds Mike
Mike Fritsch

See http://www.ttalk.info/EarlesImages.html for a series of images from Patrick Earles. One shows the innards of an oil pressure gauge. Bud
Bud Krueger

Thanks a lot for the link, that helps to better understand the mechanics.
It also explains the behaviour- when the oil pipe is under stress it may force the tube sideways, at the same time time the pointer is fixed by the faceplate, so it is easy to imagine that the instrument jams up at the tiny mechanics between the tube and the pointer.
Also seems the only place worth oiling is the area around the pointer.

Has anyone ever replaced the green stuff on the light slots?
Mine is falling to pieces
Rgds Mike
Mike Fritsch

This thread was discussed between 11/04/2016 and 01/05/2016

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.