FJ40 Brake fluid leak (2 Viewers)

[1st77FJ40]

I have a 77 FJ40 (5.7 swap) I had some smoke from my exhaust and realized it was my brake fluid dripping onto it. Specifically it’s draining the rear reservoir ( yellow circled area, ) coming from the bolt inside. I have never had to work on a master cylinder so I’m not familiar with trouble shooting it. Is it as simple as tightening the nut there on the bottom where it’s dripping or is there a seal I need to re build? Also, a side question, are these reservoirs flipped? I thought I have been seeing the larger reservoir for the front and the smaller in the rear on these dual master cylinders. Thanks in advance for all the help fellers.


Qube

 

[charliemeyer007]

Those are electrical pressure switches, so it could be leaking threw the switch or around the fitting. You could try tightening it a little and see what happens, might solve the issue if it was just loose.

I have always seen the larger reservoir on the front. Perhaps someone "rebuilt" the unit and didn't get it exactly right. A whole new unit isn't very expensive - the switch is like $30 and new cylinder's don't appear to come with them any more. Brake Master Cylinder for Toyota Land Cruiser 76-80 FJ40 FJ55 | eBay - https://www.ebay.com/itm/Brake-Master-Cylinder-for-Toyota-Land-Cruiser-76-80-FJ40-FJ55-/302973774390?_ul=IN

 

[1st77FJ40]

Those are electrical pressure switches, so it could be leaking threw the switch or around the fitting. You could try tightening it a little and see what happens, might solve the issue if it was just loose.

I have always seen the larger reservoir on the front. Perhaps someone "rebuilt" the unit and didn't get it exactly right. A whole new unit isn't very expensive - the switch is like $30 and new cylinder's don't appear to come with them any more. Brake Master Cylinder for Toyota Land Cruiser 76-80 FJ40 FJ55 | eBay - https://www.ebay.com/itm/Brake-Master-Cylinder-for-Toyota-Land-Cruiser-76-80-FJ40-FJ55-/302973774390?_ul=IN

Okay I really appreciate it. I didn’t want to go wrenching it down without understanding how it affects the cylinder. I’ll I’ll tighten it, re fill it and so what happens and if need be order new ones in my next cruiser corps purchase. Either way I’ll let you know how it goes.

 

[brian]

those are tapered pipe threads irrc, if its leaking past the threaded connection, i would expect that fitting to break if its wrenched on, as it looks like its already buried in the master cylinder.

 

[65swb45]

those are tapered pipe threads irrc, if its leaking past the threaded connection, i would expect that fitting to break if its wrenched on, as it looks like its already buried in the master cylinder.

I agree with @brian's assessment 100%. Proceed with caution. In fact, since you don't appear to be using the sensors, just buy a pipe plug and swap it in there. If you're reasonably adept, you can do it before the reservoir runs dry and no bleeding will be required.

 

[1st77FJ40]

Alright guys here is a follow up. I topped off my reservoir and tightened the electric pressure switch. ( the angle of the picture didn’t show very well but there was still about 1/4 inch on each of them) after that I left a little drip cup to see if it was leaking and it’s dry. I’m now going to bleed the system because the rear reservoir was pretty much dry previously. I’ve seen other posts here that bleeding the FJ40s is a pain so I’ll let you know how it goes.