Brake Line Woes:

[LeftAngle]

Brake Line Woes:

Lotus design can be illogical and frustrating to work around.  My car has been off the road for the past month while I’ve been attending to resolve my spongy brake issue.  The original rebuilt master cylinder’s rear brake piston was having issues so I replaced it with the Triumph Spitfire equivalent. 

As long as I was doing that I felt a set of Wilwood pressure valves might help as well.  The car’s master cylinder is mounted to the lowest point in the brake system, something I believe takes part in my braking troubles.  And that was the beginning of my brake line adventure.

Locating proper fittings to convert the valves was a monkey cluster.  Suppliers saying “ya, we got that” and sending me everything but became an every day experience (I’m a designer, not a mechanic so my skills are learned on the job).   After retooling what was sent I finally have the lines in place.  And now they have to be bled. 

For me, bleeding is a 3 person job.  One person at the brakes, one person pumping and another constantly filling the fluid reservoir.   Commandeering anyone into an unconditioned metal building in August is A fools errand.  A vacuum pump can solve one issue, but the severely reduced volume of the Spitfire’s reserve tank is something that required designing.   For $2 worth of materials, my remote reservoir fits neatly between the body and blower fan.  It’s high enough to drop a funnel in and holds enough dot3 fluid to allow me to draw a brake line’s worth at each wheel.   It’s permanent and I’m waiting for the 5200 to cure before filling it up.  The cylinder has been bench bled and ready to go so my next task is to bleed the brakes… alone.

I know I’ll get some flash back but the simplest designs are the best and this is my solution.  I’ll report back on my success or failure

[BDA]

Your reservoir looks pretty nice! One way to reduce the number of people needed to bleed your brakes is with a pressure bleeder. Here are some options. I have a Motive brand bleeder (I don't remember which model. I think different models have adapters for different M/C reservoir caps. They have a large supply of adapters but they don't have one for every reservoir (as I found out). Luckily for me, I had a spare reservoir cap that I drilled a hole in and attached that to the hose of the bleeder. With a pressure bleeder, you put some fluid in the reservoir and the tank. Attach the hose from the bleeder to your reservoir using the proper (or one you adapted) adaptor and pump up the tank to the proper pressure. You go from brake to brake and bleed out the air by loosening the bleed nipple a little while a tube is attached to the nipple goes down into a bottle with fluid in it. The tube must be below the level of the fluid of the bottle. I got a purpose made bottle with a "lanyard" on it that allows me to hang the bottle from the bleed nipple or other handy place. You can check the pressure and the amount of fluid in the tank from time to time but you are the only person needed to get the job done.

Alternatively, you could attach aa tube with a bottle as described above to each blead nipple you are bleeding.  You might also use some teflon tape around the threads of the bleed nipple, being careful not to block the bleed holes. You can pump the brakes and monitor the reservoir yourself. This will be less precise than the pressure bleeding method since you won't see when the bubbles stop forming but it doesn't hurt to pump more fluid through the brakes then you need.

One think I might mention is that most M/C reservoir caps have a vent in it that has some sort of baffle to keep trash (and liquid water?) out. I have seen cap vents were just a length of tube that was coiled a few turns (maybe held in shape with a tie wrap).

[Kendo]

I second BDA's pressure bleeder. I've bled the Europa's brakes for decades (gak) this way by myself. And I adapted the system by buying a spare reservoir cap, drilling a hole in it and adapting to the pressure bleeder's hose.

Since apparently people can get the wrong idea, we are talking about the system that positively pressurizes the MC reservoir, not the one that sucks brake fluid from the bleed screws. That way leads to madness and sudden death.

I really like your deep reservoir extension. I just work with the existing reservoir and watch to make sure I don't let it get too low.

[LeftAngle]

I figured a vacuum bleeder would work as better with no pressure on the cobbled together Spitfire MC.  If a pressure system is required, I’ll find out quickly and chances are I could make one up or only be another day or three for Amazon send one to me.  I’m letting the 5200 cure for 2 days before I get back to it. 

I’m trying to move out of the large shop and back to the house.  I thought it’d be sooner than later so I sold my 4’ diameter fan in the spring.  Bad move… it’s HOT here.  The good news is I’m losing weight😂

[Kendo]

It's really hard to get the bleed screw to not leak air with the vacuum bleeder. My ancient pressure bleeder uses air pressure from one of the tires. I always reduce the air in that tire to ~15 PSI to save the MC.

[jbcollier]

I almost always bleed the brakes by myself.

- bench bleed the master before installing
- fill up the reservoir
- attach a hose and bottle to the rear bleeder farthest away from the master
- crack the bleeder open
- slowly pump the pedal 10 times
- close the bleeder
- refill the reservoir
- repeat with the other rear brake, then the front brake furthest away, and finally the closest front brake.

How are the brakes?

I usually repeat the whole process again with just a couple of pumps and make sure the hose has no bubbles.

[LeftAngle]

Thanks for all your feedback.  Today I bled the brake lines.  It took about 4 hours and I circled the car 4 times to insure all air was removed.   It took a while for me to figure out the best  methods to get satisfactory vacuum to the lines.   The most critical thing was getting the right pressure.  I settled on 40psi at the compressor.  More than that, the vacuum drew in exterior air from the loosened threads of the brake’s bleed nipple making it appear like air was in the lines and less than 40psi slowed the flow of fluid to a crawl.  Keeping a finger pressed on the the bleeder tool’s rubber connector helped reduce false air bubbles as well.

The smartest move I made was expanding the meager Spitfire brake fluid reservoir by 15 cubic inches.   I can’t stress how great it was to be able to apply continuous vacuum to the rear brakes, drawing out large amounts of fluid without having to constantly stop to refill.  Front brakes were quicker but I still ran a large volume through the lines in one long “suck” giving me confidence that the lines were truly air free.  Job’s done now and I can go driving now… Yay! 

[Bainford]

I like the increased volume of the reservoir. Very handy. How is the new reservoir addition vented? Is there a rubber diaphragm separating the fluid from the ambient air?

[BDA]

Congratulations, LeftAngle! Another step in your journey! 

[rjbaren]

Hey LeftAngle, can you please post a few more photos of your car.  It looks great from the rear.  I would like to see more of it.

[Dilkris]

 

[TurboFource]

This is his car... http://www.lotuseuropa.org/LotusForum/index.php?topic=2219.msg20824#msg20824

[4129R]

I have just spent most of today putting fluid in a completely dry system, with new lines everywhere, and overhauled calipers and drum brake cylinders.

After much pumping, I eventually got fluid to both drums and one caliper. N/S front caliper was completely dry.

So I decided to trace the fault by undoing connections until fluid leaked.

It turned out that the rubber hose was completely blocked. Luckily I had a spare, so tomorrow I will do the final bleed to see if I have a pedal.

I have never had a blocked hose, so something else to add to the list. I was initially pleased to get fluid coming out of the pipework, but by the time I had tightened all the joints, my hands were covered. I hate brake fluid more than I hate gearbox oil. 

[LeftAngle]

Yes it burns. 

[LeftAngle]

Bainford:

I like the increased volume of the reservoir. Very handy. How is the new reservoir addition vented? Is there a rubber diaphragm separating the fluid from the ambient air?

I’ve been away from this thread for a while and didn’t see your question… a good one. 
I simply made the top threads of the extension the same as the Spitfire’s and used the vented top from that.