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checking brake vacuum, how?


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Thanks, I saw that, but you can only test for vacuum on the pump, not on a system that comes after the pump, like the hose, splitters and brake servo, as it in itself does not generate vacuum, so need the bigger set, and that is 500. I guess I'll order one from the UK if I cannot find the Mityvac here. And after a couple of hours of looking, there's none in Denmark. Only cheap plasticmodel and the one from biltema. I don't trust the biltema model. They have a bigger set for 500 and I cannot see if it can be switched over from vacuum to pressure. The pressure feature can for example be used to adjust the wastegate controlcapsule correctly ;) 

Oh well, I guess I have to import one from the states, it jsut takes many weeks plus the Price will be doubled ;)

Okay, I dound it here in Denmark and in Norway, 350 gbp.

Kind regards,

Jacques

Nobody does it better - than Lotus ;)

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Okay, I fount the Mityvac MV8500 model in the UK, so I'll order that. It can do both suction and pumping, which is handy for other Things as mentioned. They are not sold in Denmark.

BTW: can someone tell me the value of the vacuum needed within a normal functioning range on the brake servo system on my SE?  I know the value of the wastegate control moduse, but not he brake servo value.??

Kind regards,

Jacques

Nobody does it better - than Lotus ;)

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  • 2 weeks later...

I'm gonna play devils' advocate and say I like the Delco system just fine. Now if y'all getting rid of it could mail me your ABS Pressure Switches, that'd be grand! :D 

  • Like 1

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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  • 2 weeks later...

Thanks Barry.

I set up the test earlier today, by separating the hose where the plastic T is, close to the one way valve at the brake servo vacuum unit in the frunk.

I have looked at all the fasteners and they are tight. I wobled the rubber bromet on the one way valve at the servo, and it's tight.

I pumped the mityvac to make vacuum and there's no leak. I reversed it and pumped it to positive pressure, and tehre's no leak. Needle on gauge is rock steady.

I inspected the plastic T and vacuumed it too, both the T at the vacuum pump on the engine and the T in the frunk. No leaks.

I tested belt tension and  brackets etc on the pump and it's all fine.

I then reassembled it all minus the small rubber hose from the frunk T to the electrical warning lamp. Instead I used that think T to connect the Mityvac to see if it did something at all. To make it Work, I had to insert a small plastic thingy between two pieces of clear hose to step up in diameter. I don't think this setup was completely airtight. I then stated engine, and it read 0,63 KPa - ,063 bar.

When I stopped the engine, it relatively quickly lost any vacuum to zero. Note: only in this particular setup. As mentioned, if I inserted the Mityvac in the other end )seperately) it's dead airtight.

I pumped the brake pedal 6-7 times to remove any vacuum, and started the engine Again. It quickly build up vacuum and brake pedal went a bit soft and down as it should.

I should maybe try to make the 3'rd setup more airtight, as I cannot trust the 63 KPa. If tight, it may show more.

Where can I find any Lotus info stating the KPa (or bar or psi) that the system should be able to produce?

I cleaned the filter on the Servo last year. Clean and still clean.

Is there a similar filter on the pump itself?

Kind regards,

Jacques

 

 

 

Nobody does it better - than Lotus ;)

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For reference, my G-car (with a common plenum & EFI) idles about 50 kPa, and gets down to 20 or so on overrun, which is where a "normal" car without a vacuum pump would be to run a vacuum brake booster.  My vacuum pump is removed, so I can't give  you better numbers.

IdleMAP1.png

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Thanks Thomas,

I suppose the value I got is not totally out, then.

Would like to have a bit more brake servo action, though. But keep it as it is, with no electrical installations.

Kind regards,

Jacques

Nobody does it better - than Lotus ;)

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  • Gold FFM

63kpa sounds quite reasonable. Might drop a bit further if you increase revs. The loss of vacuum in the last test is probably through the vacuum pump, which is to be expected. A good further test would be to put the mityvac in place of the vacuum pump. Other than maybe a (slightly) worn vacuum pump, your system seems to be in good shape. I personally like the fact the brakes in the Esprit require some force. Much better than many moderns that have very touchy brakes.

Filip

 

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I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

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Thanks chaps!

Filip: I don't think so, as the direct connection of the Mityvac to the pump through all of the hose from the braks servo unit, showed a steady non-moving vacuum test. I let it stay for an hour. I think it was my fittings that were not securely tight in the thrid setup, which produced the loss of vacuum.

So, I'll set it up again directly before the T right after the pump itself and take  a measure. I'll need to make the connection airtight to make sure the readout is valid.

Meanwhile, I have got another T for the replacement of the T right after the pump itself.

Kind regards,

Jacques

Nobody does it better - than Lotus ;)

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