Gt6 Mk1 repeatedly blowing fuse - it's back

[Peter Truman]

Would a multimeter continunity test ie the buzzer determine if there is any polarity, ie each lead to the solenoid  body in turn if no buzzer or continunity signal then I presume the solenoid is not polarity sensitive.

Any comments advice from those electricity charged appreciated!

[Pete Lewis]

well a google of the conundrum

 

People also ask

How do you determine the polarity of a solenoid?

A: Two wire solenoid valve coils do not have any polarity requirement (i.e. you don't have to worry about mixing the positive and negative wires).

Does a solenoid have positive and negative?

A: Two wire solenoid valve coils do not have any polarity requirement (i.e. you don't have to worry about mixing the positive and negative wires).

Edited August 15, 2020 by Pete Lewis

[Colin Lindsay]

Excellent! Thanks guys, it's being fitted today regardless and as I said to the man from whom I bought gearbox oil a short time ago - it is NOT all coming out again. That one lasted me almost twenty years, so here's to the next 20 with a gearbox tunnel that stays put. To think that all this started with a blown fuse... rebuilt wiper motor, replaced CD player, replaced indicator stalk, replaced O/D stalk, rewired O/D loom, replaced O/D and reversing light switches... and all because of the solenoid...

[daverclasper]

Good luck with the new solonoid.

In case you still want to mess with the old one. I rebuilt one about 7 years ago.  When removed, it didn't clack when shaken and was a gummed up inside. Cleaned up and new o rings and clacked like a good un. I seem to remember the movement was small when energised (maybe about 1.5mm) I think this movement info was on Buck eye, though trouble with computer at the mo, and everything taking ages so can't confirm.

Quite recently there was someone on this site selling his surplus orings very cheap, as he had bought quite a few, though can't remember who.  

[Colin Lindsay]

35 minutes ago, daverclasper said:

In case you still want to mess with the old one. I rebuilt one about 7 years ago. 

The plunger won't come out; it stops at the end pf the brass arm and will not move any further - tips on removal?

More importantly - the new solenoid is fitted, but as before failed to work at all. The switch made no difference to on or off. I tried it with both ignition on, then engine running, but no difference; HOWEVER when I moved the gearstick between third and fourth it started to click. If I hold the gearstick to the right, it works; if I release it, it stops. I've rebushed the gear remote levers so this points to the cam not fully activating the switch when the stick moves to third or fourth. 

I have three options here: replace the switch - which I already did but with a different version to the original, which shouldn't make any difference to operation;

Bend the switch bracket so that it sits closer to the cam;

Or move the cam.

First two are simple; is the last option at all feasible?

 

[Peter Truman]

I pulled the plunger out after taking the cap out by inserting And screwing a small self tapper Into the hole in the piston rod then pulling it out.

Colin you are having fun hope the switch bracket is the end of the tunnel

[Pete Lewis]

bend the bracket 

adjustment of these switches  was by a card washer , doesnt help if travel is insufficient 

Pete

[Colin Lindsay]

3 hours ago, Pete Lewis said:

bend the bracket 

Done that. Seems to be working every time now, need final fettling of things before I can hang up the spanners for the day. Why does it feel like a bodge? Why do I feel guilty? 

 

[NonMember]

43 minutes ago, Colin Lindsay said:

Why does it feel like a bodge? Why do I feel guilty? 

Because you're over-thinking things and assuming it's over-engineered. Bending the bracket is the official manufacturer method.

[Colin Lindsay]

Thanks, my friend, you know how to cheer me up! It's in, it works and the guilt is fading... to be gone completely once the gearbox tunnel is refitted and hides everything.

(Actually I took it off again, straightened it in the vice and then rebent it with loving care... so it feels more... professional, and I feel more like a real mechanic.)

[Pete Lewis]

Colin if you feel guilty over a little bending  do not go down a Body in white assemble line 

with ulta modern jigs and robots there is still a guy with large padded lump of wood for getting the door set in the aperture   you would  have a baby   !!!!

the only missing is there is no specified tolerance quoted  for,.............. 'bending'  

Pete

[Colin Lindsay]

Before I finally close this mega thread (I was going to say put it to bed but you know how it goes on here) I've managed to get the plunger out of the old solenoid, cleaned it up a bit and now that it plays the maracas might keep it as a spare. However: I can't find a source for the small circlip at the end, which broke into rusty bits when I removed it. Any sources?

[daverclasper]

Dave Twigger at, OD spares, Rugby (I bought 2, one as a spare). There were only a few pence. I think I sent a SAE and extra stamps for the value of the clips + some orings for solonoid and pressure relief valve. He's was dead friendly and helpfull.

Out of interest, how did you release plunger?.  

[Pete Lewis]

+1 for dave twigger ...........always helpful  

its around 10mm but i dont have one to measure 

 

Pete

[Peter Truman]

Have a dismantled J Type solenoid on the bench, the circlip is 10.1mm uncompressed outside diameter, by 0.96mm thick

[Colin Lindsay]

4 hours ago, daverclasper said:

Dave Twigger at, OD spares, Rugby (I bought 2, one as a spare). There were only a few pence. I think I sent a SAE and extra stamps for the value of the clips + some orings for solonoid and pressure relief valve. He's was dead friendly and helpfull.

Out of interest, how did you release plunger?.  

With the circlip removed and the cap and spring also on the bench I moved the plunger moved forward with light tapping of the outer casing, I used a plastic-headed hammer, but it would not come fully out; it just sat right at the end. I tried a pair of pliers in the end, pressing them outwards to wedge into the plunger but no go, so eventually managed to get the head of a small screwdriver in to the end of the plunger and by wedging it sideways got enough pressure to pull the plunger out. 

The plunger is heavily gunged up, so I cleaned it and cleaned the solenoid case out with carb cleaner aerosol; once I put it back in again it rattled as it should. If I can get the circlip for the end I'll maybe replace the o-rings that I can see, as I don't want to open the case and repair to destruction.

 

 

[Pete Lewis]

its getting  there  yes  leave the case well alone ,  you know if you mess any more disaster will strike big ice burg small boat ...no hope 

so now youve got a new solenoid ,  new switches , bent the mounting bracket and rewired half the car 

does it all work without blowing fuses ????

Pete

 

[Colin Lindsay]

28 minutes ago, Pete Lewis said:

does it all work without blowing fuses ????

Pete

 

Yes. LEAVE IT ALONE! Ok. Now, with regards to the other one...

I'd love to see into HIS garage..

[Colin Lindsay]

The problem is back again.

TSSC Northern Ireland run today, we did about 40 miles with fully working overdrive, no problem. Headed off on the run, over some very hilly mountain roads, rain came on heavily, I had wipers, screen blower and radio all on, then the fuse blew. Replaced it and got about 300 yards, blew again. Pulled in where I could, replaced it again and it blew immediately - this was with everything turned off. I had to leave the run and head for home. Over the next three or four miles I went through 13 fuses. They didn't blow immediately; some lasted maybe a mile then blew. 

Then I realised it blew quite quickly when I hit third gear - hence the O/D inhibitor switch was being activated. I drove for five or six miles in second - no problems. When I came to the motorway I went to third and fuse blew immediately; replaced two within 100 yards and finally pulled the two bullet connectors on the bulkhead for the reversing lights / O/D circuit. After that, no more fuses blew - just as well as I was down to my last 3 for the forty miles home.

I've rewired that entire loom from the bullet connectors to solenoid; replaced the column switch, replaced the reversing and O/D inhibitor switches, and replaced the solenoid itself, all new items, connectors and wires. It doesn't matter if the O/D is on or not, the fuse still blows on selecting 3rd gear. I can have as many other things running on that circuit as I want - radio (including sat-nav charger via USB) wipers, indicators, heater blower - nothing blows it until I select 3rd, then it goes. With nothing else running on that circuit, all else turned off, O/D still makes it blow.

I'm climbing the walls here but cannot work out the cause. Any thoughts?

[dougbgt6]

Colin, 

I suspect it’s the O/D inhibitor switch! 😊

You’re going to have to take it apart, isolate it and do some testing, applying voltages. Tomorrow. Tonight some golden throat nargler.

Doug

[Pete Lewis]

so does it blow if you avoid 3rd like go 2nd to 4th  ???   i dont see 3rd being anything to do with the short , in as much 4th operates the same switch 

so the switch or its wires are the common thing not  3rd  if thats follows 

Pete

[Colin Lindsay]

8 minutes ago, Pete Lewis said:

so does it blow if you avoid 3rd like go 2nd to 4th  ???   i dont see 3rd being anything to do with the short , in as much 4th operates the same switch 

so the switch or its wires are the common thing not  3rd  if thats follows 

Pete

I'll check that by Monday at the latest, but don't forget that it's column-switch activated so there are no switches or wires near the gear lever but I'd assume that it will blow in 3rd or 4th - it's just that I get to 3rd first! I've replaced the switch Doug so doubt if two have the same fault, as they're different brands of switch and different shapes.

It has all run perfectly for over 15 years, but only started blowing in January this year and has done so ever since. Am I correct in that, by removing the overdrive circuit, I've isolated the fault (since it hasn't blown since) therefore the fault is on that side of the loom, and can't be before the bullet connectors as it would still have blown even after disconnecting the circuit further along?

Doug's second point is uncannily accurate - just been to the offie. Tonight the GT6 will be but a hazy dream.

[Pete Lewis]

you dont have some daft polarity mix up with the reverse circuit ,

pete

[Colin Lindsay]

9 minutes ago, Pete Lewis said:

you dont have some daft polarity mix up with the reverse circuit ,

pete

No; it was completely untouched for years and started blowing whilst still unmolested, so it worked from about 2002 when originally fitted, then I fitted a new loom during the restoration back in about 2004 / 5. I can't rule out the reversing light circuit, as the rear panels were replaced in December and the car returned to me in January, which is when the fuses started to blow, but if that's the case surely it would also blow if reverse was selected? I've wondered about a short in that circuit as I refitted the lights after getting a new rear panel and boot floor, but again surely it should blow when reverse is selected, not O/D?

[NonMember]

I remember when you were investigating earlier that it wouldn't blow if the column switch bullets were disconnected. Try that test again because, given that it only blows when the inhibitor is closed (3rd gear) but irrespective of the overdrive column switch state, the problem is somewhere between the inhibitor switch and the column switch. If you disconnect that bullet it will tell you which side of that the problem lies.