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Re: Exchanging the brake servo

PostPosted: Wed Aug 21, 2013 11:38 pm
by billwill
Pistacchio sprint 72 wrote:Another question! Engine on so the servo gets the vaccum it needs or engine off?

Car is rhd



Engine off, the inert servo will make the pedal a bit harder to push, but it should still go down oK. You only do it slowly in any case.

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 5:44 am
by Pistacchio sprint 72
pharriso wrote:
Pistacchio sprint 72 wrote:I have a small girling tank and a bigger one... The level in the big one is low...


Larger Girling cylinder = brakes ; smaller = clutch master cylinder

Cedric, remind me, is your car LHD or RHD?


Is there another bug in the workshop manual??

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 10:28 am
by andyelan
Hi There

Yes and no!!

The diagram is correct in that (on a RHD car) the brake cylinder should be to the right (looking forward) of the clutch cylinder as shown - otherwise it might be rather difficult to connect up to the pedals

I agree however that it should be shown as the larger of the two cylinders

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 10:40 am
by MickG
East to confirm just follow the brake lines from the servo to the master cylinder. On my Sprint and I would expect it to be the same on all, the larger of the two adjacent master cylinders is the brake. Another easy check is to see which cylinder is connected to the brake peddle. :D

Mick G

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 11:30 am
by Pistacchio sprint 72
I purchased one liter of brake fluid this morning and some tubing.

I will top both tank anyway!

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 3:27 pm
by Pistacchio sprint 72
Cheers! :mrgreen:

Done!

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 3:53 pm
by oldelanman
It's a good idea to have the end of your bleed tube immersed in the fluid in your beer glass - you can then see when all the air has been expelled as there will be no more bubbles. :wink:

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 6:35 pm
by billwill
andyelan wrote:Hi There

Yes and no!!

The diagram is correct in that (on a RHD car) the brake cylinder should be to the right (looking forward) of the clutch cylinder as shown - otherwise it might be rather difficult to connect up to the pedals

I agree however that it should be shown as the larger of the two cylinders


Nope! in a right hand drive car the bigger master cylinder (the brake) is nearer the engine to the left of the smaller clutch master cylinder,. The pedal linkages must cross over somehow, but I don't recall exactly how that is done.

Image



The diagram
Image
is wrongly labelled.

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 6:43 pm
by mbell
That's strange, my RHD +2 has the large brake on the outside/drivers/pedal side and the clutch on the inside.

Is this a +2/elan difference? I would think it very strange for them to cross the pedals, complication for no real reason.

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 6:52 pm
by billwill
My photo and the diagram are for a 2-seater not a plus 2.

It looks like a totally different arrangement. with your cylinders facing the other way around.

The parts diagrams dont seem to help much on how the pedal forces cross over.

Two-seater:
http://www.rdent.com/manuals/elan/brakes/jf.htm



Plus 2
http://www.rdent.com/manuals/plus2/brakes/jg.htm




.

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 6:59 pm
by oldelanman
mbell wrote:That's strange, my RHD +2 has the large brake on the outside/drivers/pedal side and the clutch on the inside.

Is this a +2/elan difference? I would think it very strange for them to cross the pedals, complication for no real reason.


There is a reason.......

In the RHD Elan there is not room for the brake master cylinder immediately behind the brake pedal so it is moved to the inside of the clutch master cylinder. The pedal box caters for the offset.

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 7:49 pm
by robertverhey
Yes the pedal pivot mechanism in the two seaters is an ingenious piece of design. If they'd made it fully dismantle-able it would even be brilliant.

Re: Exchanging the brake servo

PostPosted: Thu Aug 22, 2013 8:01 pm
by mbell
Thanks Bill, Roger.

So its a plus 2 difference, on the Elan the master cylinder are in-front of the peddles operated by the "peddles" before their axis points. With the Brake and clutch reversed relative to the pedals, for space reasons.

The +2 has the master cylinders above the pedals, and operated by an extension of the pedals past the axis point. Therefore the master cylinders are installed facing in the opposite direction.They also no need to reverse which side they are on due to the extra space in the engine bay.

You learn something new every day.....

Re: Exchanging the brake servo

PostPosted: Fri Aug 23, 2013 2:27 am
by billwill
mbell wrote:Thanks Bill, Roger.

So its a plus 2 difference, on the Elan the master cylinder are in-front of the peddles operated by the "peddles" before their axis points. With the Brake and clutch reversed relative to the pedals, for space reasons.

The +2 has the master cylinders above the pedals, and operated by an extension of the pedals past the axis point. Therefore the master cylinders are installed facing in the opposite direction.They also no need to reverse which side they are on due to the extra space in the engine bay.

You learn something new every day.....


Yup!

I must look more closely at a Plus 2 engine bay next time I see one.

Re: Exchanging the brake servo

PostPosted: Fri Aug 23, 2013 9:59 am
by Hongokongo
Sorry to hijack this topic, but is the servo shown in the first picture a Lockheed type or
Girling type? The reason I ask is that on my fairly newly acquired +2 I have the same problem. The servo is about five years old, but has hardly been used. It may be a Powertune RLE72696. I have cleaned the piston a couple of times with no success. I have also checked the angle, between 25 &45 degrees. What can I check next, or do I bite the bullet and get a new servo?