Servo problem with Twin Weber carbs

So…just had new twin Webers ICT 34’s fitted. Engine runs perfectly, really pleased. Only problem is whilst oomph has increased by perhaps 30% my brake efficiency has decreased by about the same %. So now great up hills but panic going down them View attachment 139477
The carbs have a balance pipe fitted T’d off to the original servo. The garage didn’t check the non return valve so possibly/coincidentally this has become faulty. I am told that the take off from the manifolds is 8mm I/d but with the Barb may be as small as 6mm.
Im due to take the van back in next week to have the valve checked but thought I’d see whether anybody has encountered this problem and any remedies if it’s not a faulty valve.
Thanks in advance View attachment 139478 View attachment 139478

 

Is the balance pipe actually porting straight manifold vacuum? Did they actually fit a non-return valve (round the right way)? Does the engine idle ok?

If the servo wasn't working, I'd expect the brakes to feel a lot worse than that, TBH.

 

I’ll check with them next week but afaik the balance pipe ported direct via barbs into the manifolds and then T’d off.
The servo is an original one ‘71 as seems was the valve. I assume that the valve was put back the right way round …but ? I would think it more likely that this may be the cause rather than a strange coincidental failure of the valve.
The engine idles and runs terrifically
Yes the brakes don’t feel good at all whereas they were very good. I had the rear flexy hoses and the solid pipe replaced by them whilst engine out. The pedal is firm so does not seem a bleeding issue ( though it is ! )
Do you think a 6-8 mm pipe sucking the servo is big enough. Previous set up was about a 10mm I/d take off from the single carb which can be seen on this photo( attached just behind fuel pump)

 

From experience - yes.
Haynes describes fitting the servo the one way valve backwards.
If the pedal now feels very hard, the servo isn't working.
Servo test is:
clutch foot on brake, start the engine, pedal should drop 1/2" or so if it's working.

 

6/8mm does seem a bit small. When I put my remote servo in, the vac pipe was at least 10mm, prob 13mm ID.

 

It'll work just fine - been there done that.

 

I don’t remember describing the servo value like that

 

Have you been on the ale, Baz?

 

Might have

 

Another bad Chelsea day ?

 

That’s what the mechanic said…But I am starting to think it may be the valve, failed or back to front….hope so

 

@Huyrob have you done this? Outcome?

 

Attachments won’t open

 

Going to try this later

 

Pumped the brakes, started engine with left foot hard on brake pedal, felt very,very little ( if any) travel on the pedal.
So seems servo not working. I hope that the valve may be faulty or put in the wrong way round….probably an easy mistake to make .

 

There's an arrow on the valve which should point towards the engine (IIRC!).

 

Thanks, I’ll get them to check it in the week, just hope it’s this as I’m sure many others with twin webers and a servo would have encountered a problem if the balance pipe supplied was insufficient I/D.

 

It pretty easy to check yourself mate no need for it to go into the garage.

 

I know but as I’ve just spent over £3k with them I’ll let them get cold