Just purchased 2002 e825-4 where to start rejuvenation?

Update, I was sent the wrong rear wheel cylinders so I popped the LR brake to verify and found seeping cylinders and wet shoes. At ~$70 for rear shoes, I think not only will I be cleaning them but I’m going to pull the shoes from the front brakes I’m sending back as a core. There must be gold in these brake shoes.

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Darn it, the brake shoes are held on with some big washer like disk with what looks like a rivet and I can’t get the front shoes off.

UPDATE: Thanks Rodney for explaining that it’s really a big pin socket the shoes ride on. I was able to get the off once the wheel cylinder and a spring were removed.

And now I know why it took 2 feet to brake previously. Not only were the 2 rear brakes all wet with leaking brake fluid but one of the front was slightly wet too. The thing should have been pulling to one side but it wasn’t. With dry brakes in the back and new discs in the front it brakes VERY nicely now.

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Just put in the new LED headlights. Pretty much a drop-in replacement. But I might design some small crescent shapes and 3D print them to make it more of a complete fit. The new ones are a bit narrower top/bottom than the originals so there’s a tiny gap top/bottom.
It’s dark outside now so I went for a ride and these are bright. Defaulted they seem to be pointed straight ahead so the 2 bright rectangle regions are nicely parallel and with a small gap between yet fills the lane up ahead without bleed into the next lane. And there’s no neat off these things where the old ones would be hot on even a short drive. Yay on the inexpensive LED headlight replacement.

Here’s a couple of pics of the new disc brakes installed


I’m interested in the LED headlights: what did you install and where did you find them? thanks

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I got them on AliExpress, the product title: 2Pc Car LED Work Light Offroad Lights 20W 6500K Spot Beam Led Chips Flood&Spot Driving Lamp Sportlight for 10-30V DC Vehicle SUV

here’s the link:

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Picked up a 120V 200A power management monitor where the display is wireless and both units(sender/display) were ~$25. Put it in yesterday off of the B- leg of the motor controller. Seems to work pretty good but I don’t yet know what the drain on the batteries are. In milliAmps so I’m not too worried. Today I saw just over 200A on accelerations and once cruising up a slight hill it was stead around 80A.


I finally received my bluetooth serial port( HC-06 ) and fairly soon will wire up an Arduino ProMini or Nano and put some temperature sensors on the motor case. All before I start looking into tweeking the programming in preparations for installing a used 7.5HP motor.

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Hey Doug. Fellow OBecian here. I just bought a 2002 like yours. I read you replaced your headlights. They still working well? I did some night driving the other night and realized a headlight upgrade is probably in order. We’d like to drive to liberty station at night but I don’t feel comfortable doing that with these stock ones. Thanks.


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Yes, working great otherwise I would have posted to this thread.


We just had lots of rain in SoCA and I did have to run the GEM in it some and it was parked outside so she saw water and lots of it. A couple of days after the rain I went to take her out for a spin and when I got back and gave her 110VAC power to charge there was a 2 tone beeping coming from the Zivan and the dashboard LED was blinking yellow.

I looked up the code and it said the temperature probe was out of spec. Recalling that the temp probe was on a plug at the top of the Zivan charger, I unplugged it and was able to recharge the batteries. Looking at the sensor, it was in the bottom of the battery pan so it’s probable there was water in there and if the potting compound or seal had cracked, water got into the sensor.

My question for the group is what part is in the end of that cable so I can replace it since after 4 days of warm weather it still says the sensor is out of spec?

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Rodney says to run without it.
The Delta-Q uses a 10k thermistor. Pretty standard.
I don’t know what value Zivan uses.
Check value at charger and at sensor to see if its the same. Might be a connection.
If sensor is open or shorted it is most likely bad.

ha, if it’s just a thermistor then I might have a replacement in my 3D printer parts bags.

The fact it worked perfectly before the rain and even after I ran it for a bit in the rain and only failed a few days after having had to sit through heavy rains and the end at the batteries(sensor end) was wet I’m pretty sure it got moisture inside an is effecting its resistance.

I’ll dig around for what it’s valid resistance range is, make a measurement and see if something in my parts bins works.

I was going to zip-tie it to the metal battery post since that’s the best place to measure battery temp but like many things, I didn’t get to it in time.

The temp sensor is an LM335 IC

And the DIN connection is to pins 4 and 5.
Order is 1-4-2-5-3

Interestingly, I clipped off the sensor at the end of the outer casing(red and blue wire coating left on sensor end for patching later ) and yet when I plug in the DIN connector I still getting the blinking yellow and beeping warnings.

Eventually, I will open the DIN connector and see what gives. I was hoping for at least keeping the charging LED.

Nice blog on LM35 and LM335 sensors


hint: common LM35( I have bunches of these ) is rated output in C while the LM335 output is in K( as in Kelvin)

Thank you for the heads up on the lights. I just purchased them on amazon !

Any other recommendations?

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Watch the the Bolt thread.
A lithium conversion that may overcome the weight distribution problem with early model Gems.

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Finally testing the 79.5V Trickle Charger using a 24V 5A surplus wheelchair charger($14) and a 1200W 12-83V-Out DC-DC converter($14). It had been charged the night before and by morning the float charge on the batteries was 75V. It is still a hack in progress and currently cost only $14 since I already had the other part(s). I will also be looking into a Zivan NG1 upgrade option to see if not only can it be upgraded to enable/include this trickle-charge feature but the Lithium charge capability too. And at what cost.

1200W 20A DC Converter Boost Step-up Power Supply Module IN 8-60V OUT 12-83V(6.8)

DC12V Power Supply 24V 12V 5A Power Adapter 110V 220V AC to 12 volt Transformer 10A 15A DC24V Power Supply for LED Strip

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after leaving it on the trickle charger for 24 hours I was noticing the voltage kept at 79.2 - 79.5 with small periods of no charge current and others with only .4A so it seemed to work well.

On the first test, I was pleased to find it did a good 24 MPH up most of the slight hills and the top of the slight hill it did as before and only held to 22 MPH and then had 91% charge when stopped. What was strange was when 2 hours later I powered back up and saw the SoC was then at 75%.

I think I need to seek out where the current leakage is coming from and find where that 12V DC-DC converter is located. I did not see it under the dash last night when I checked on the trickle charger.

I finally got the LM335 parts from China and replaced the one on the problematic battery sensor but it was not the LM335 which was bad. You see, built a little Arduino circuit with the LM335 and a 1K resistor and a raw LM335 worked fine but when I jumped in the newly replaced tiny circuit board from the battery sensor, it showed -100 F. Wrong. Removed the tiny surface mount capacitor and it was shorted. Grabbed something of similar physical size from a scrap circuit board and after installing it, the sensor module worked fine.

I have some thick silicone heat transfer compound I will try encasing the LM335 in and then heat shrink it and maybe even insert a metal tab so it can be attached to a battery post for best battery temp measurements.

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