Got a leaky master cylinder...92 Q

[lonallenq45]

Anyone here have this problem? I kept seeing the brake light on the inst. panel come on and it was usually with a cold snap. Thought that the colder fluid must have been getting denser and getting low. Then I started getting a burning smell once the engine was warm and the odor is coming from behind the engine. Finally after a few days I get a small puddle on the floor. Turns out to be brake fluid but I could not figure out from where it was leaking. Today I had the wife depress the pedal while I observed. Found a small drip (one drop every over second) coming off the bottom of the master cylinder. Not sure if I will have to replace the entire thing or what.

Wanting to know if any of you have had similar experiences and what you had to do to fix it.

TIA

[jtesensky]

There's no re-seal kit as far as I know, but you can get the bottom reservoir seals, who knows if that's where you are really leaking from. The assembly itself isn't too bad in price, $159.63 for NICO members. I have never heard of anyone trying to do a re-seal on the reservoir though, couldn't tell you how much work it is.-Joe

[911/Q45]

I tried to rebuild mine, without success it was internally corroded, so I recommend a new unit.

[lonallenq45]

Thanks guys.

I will try and see if it is just the bottom reservoir seal before ordering a new one from Joe.

[Q451990]

There is a rebuild kit available and instructions in the manual, but with something as important as brakes, I decided not to take the chance. Tom (former parts mgr. at Infiniti of Lisle) said he'd never sold a rebuild kit, so who knows how old the seals in the kit would be...

The best deal on the master cylinder that I could find was from http://www.importedcarparts.com/ (use part number n3000-52312) for $121.07. This is a new master cylinder from Tokico. It comes in the Tokico box (not Nissan) but the part number on the box is 46010-60U11, the same as the Nissan number and it has 60U11 stamped on the unit as well - so I'm sure it's the same thing.

I ordered mine last summer and it showed up with no problems in about a week.

Heath

[90Q45blue]

I have the same problem with my car. I couldn't figure out why the brake light kept coming on and was about to post in the mechanic section but it's nice to have that figured out now. Lately, I've just been pouring in more fluid when the light comes on until I can afford the new master cylinder. How hard is that to install and what's the estimated time for a mechanic to do? Hopefully we're not looking at like an 8 hour job.

Nick

[EWT]

Anyone here have this problem? I kept seeing the brake light on the inst. panel come on and it was usually with a cold snap. Thought that the colder fluid must have been getting denser and getting low. Then I started getting a burning smell once the engine was warm and the odor is coming from behind the engine. Finally after a few days I get a small puddle on the floor. Turns out to be brake fluid but I could not figure out from where it was leaking. Today I had the wife depress the pedal while I observed. Found a small drip (one drop every over second) coming off the bottom of the master cylinder. Not sure if I will have to replace the entire thing or what.

Wanting to know if any of you have had similar experiences and what you had to do to fix it.

TIA

I had a similar problem with my 93 and replaced the master cylinder with a rebuild. It's been a few years, but I think it was a pretty easy job. Just make sure to have a good set of flare wrenchs on hand so you don't round off the brake lines. Also, installing a set of Speedbleeder bleeder screws on the calipers will make the subsequent brake bleed much faster and easier.

[Q451990]

Nick,

You need to verify that it's the master cylinder that's leaking... Check for fluid running down the vacuum booster. Also check around the ABS actuator on the other side of the engine bay firewall. It's a common problem as well.

Heath

[lonallenq45]

Nick,

You need to verify that it's the master cylinder that's leaking... Check for fluid running down the vacuum booster. Also check around the ABS actuator on the other side of the engine bay firewall. It's a common problem as well.

Heath

I second the mention of the ABS actuator. My next door has a 91 M30 that was loosing brake fluid at the ABS actuator. Called Joe for a price ($1700 for the M30 and $1200 for the Q through him). There are no rebuild kits for the older units and all you can do is replace the unit. He tells me that it is common for them to start leaking and to keep an eye on it. After replacing the fluid on the M30 and bleeding the brakes the leaking has stopped. The old fluid was as brown as used motor oil. I am sure it will come back though. Neighbor is contemplating selling the M30.

[90Q45blue]

Well crap, how did this turn from being a possible $200 job to costing $1300?

It is snowing like crazy and it's 14 degress outside so when it warms up and my baby isn't buried in snow I will check to see whether i can buy the master cylinder now or dip into the "nick buys another Q" fund.

Nick

[greg_atlanta]

Mine has had a slow leak for a while and only lost fluid in colder weather, but now I have to top it off once a week... might as well replace soon.

Did have a master cylinder fail outright on my '75 Volvo 164E and that was interesting... car would stop, but only with significant lead times and the emergency brake holding me in place at every stoplight!

[maxnix]

Quote »The old fluid was as brown as used motor oil.[/quote] Every technician and service writer with whom I have discussed ABS acutaor failures always cite old, moisture laden fluid. It is impossible to see the moisture, so change the fluid.

[Q45tech]

Failure to change brake fluid and flush entire system everytime pads are replaced [30k] unfortunately this tends to not show up as a problem till after the 60k warranty expires.

[Q451990]

The ABS unit is availabe as a rebuild from A-1 Cardone... think under $500, not thousands. If it comes to that let me know and I'll try to find a good source for you. I replaced mine with a remanufactured unit a couple of years ago with very good results! The 93's apparently had updated seals, so you might find one of those in a salvage yard and replace it that way too.

And the master cylinders are very common leak items - if yours hasn't ever been replaced in 245K it would be unusual. Just look for the leaking fluid and take it step by step and you'll be fine.

Heath

[lonallenq45]

Mine has had a slow leak for a while and only lost fluid in colder weather, but now I have to top it off once a week... might as well replace soon.

Greg,

Do/Did you notice that the leaking fluid was causing a burning smell from under the hood? I think that some of the fluid is getting on part of the engine or exhaust manifold and once the car warms up I get a burning smell (not strong, but every now and then the odor is pulled into the cabin by the vent when sitting at a light and that is when I really notice it). The odor is strongest near the rear of the driver's side and I can only attribute the smell to the fact that the fluid has started leaking. For the past few days it has not leaked much at all and the temps have been in the low to mid 70's. A cold snap is expected tonight so tomorrow I will see if the leak gets worse. I am betting that the seals under the reservoir are the culprit and replacing them should be cheap.

[911/Q45]

I tried that with mine and just wasted time and money. The seal under the reservior is an O ring and it is just about impossible to seat the reservior back into the master cylinder fully without removing the entire assembly. Plus, that wasn't the problem!Save yourself the aggravation and downtime and get the whole master cylinder.

[greg_atlanta]

Greg,

Do/Did you notice that the leaking fluid was causing a burning smell from under the hood? I think that some of the fluid is getting on part of the engine or exhaust manifold and once the car warms up I get a burning smell (not strong, but every now and then the odor is pulled into the cabin by the vent when sitting at a light and that is when I really notice it).

Mine just slowly oozes down the back of the firewall. Seems it would have to splash around to get on the exhaust manifold.

Might want to check your power steering fluid and hoses.