Chev EK

EK283 · Post by **EK283** » Thu Mar 17, 2022 9:15 am

Thanks Harv,

The material they are made from is polyamide based (PA-T) techno polymer.

The only warning it gives is to avoid alcohol, so i'm a bit worried about that in brake fluid ????

Greg

Harv · Post by **Harv** » Thu Mar 17, 2022 10:01 am

Interesting.

Polyamides are a fancy name for nylon. Nylon is alcohol and brake-fluid tolerant.

The -T bit probably means its an aramid (like Kevlar). Aramids can be touchy about compatibility, depending on which one it is. Would need the actual polymer name to hunt it down.

Cheers,
Harv

EK283 · Post by **EK283** » Mon Mar 21, 2022 12:20 am

Ok guys,

So I finished my brake booster install and the brakes are just great, good feel and little foot pressure, really feels like a new car brake wise !!!

BUT, I am going to say Neil is correct in saying that 14hg of brake vacuum is not enough for 3 or 4 constant applications, after this the brake pedal goes hard due to the vacuum pressure drop and slow recovery.

So I am now looking at a vacuum pump, bloody hell it never ends !!

Any suggestions or experiences on vacuum pumps please ?

regards Greg

oz_ek · Post by **oz_ek** » Mon Mar 21, 2022 7:50 am

Could you use a vacuum reservoir?..... https://www.youtube.com/watch?v=0OMIzCvYefY

Some info..... https://help.summitracing.com/app/answe ... anister%3F

Harv · Post by **Harv** » Mon Mar 21, 2022 8:11 am

I had the same problem at 13"Hg - good pedal for the first few stops, rock hard thereafter.

I've got the PBR VH151 booster From a TC-TE Gemini, with the PBR P6258a master from an XA/B/C &*#@. I added to the VH151 volume (1.4L) with a Protek VT1 vacuum tank (3.1L). I have no manifold connection, but instead use an Aeroflow AF49-150 electric twin piston vacuum pump controlled by a Hobbs switch. I sourced the tank, pump and switch from Hoppers Stoppers.

The Aeroflow pump is good - cycles on and off and is quiet (can hear it hum when the engine is off, can't hear it over the engine... unlike the Holley Red pump, which sounds like Johnny Cash in the boot). I've done a fair bit of stop/start driving, and it keeps up OK. Craps me a little that the pump comes with no maintenance instructions... it appears to be made to be a throwaway unit.

The tank is a nice finish, and the connectors are tight. I made the mistake of mounting it in the engine bay though... should have tucked it up under the guard.

Cheers,
Harv

Errol62 · Post by **Errol62** » Mon Mar 21, 2022 10:04 am

Torana boys are using aHella UP28 pump from a SIDI V6 VE Commodore to assist engine vacuum. The word is they are cheap and quiet, but not suitable for stand alone application such as Harv is using.

Stand-alone system they are using Hella UP5x and apparently it is quiet and kicks arse.

FB ute fixer upper, EK van on rotisserie

FireKraka · Post by **FireKraka** » Mon Mar 21, 2022 11:21 am

Hey guys I use the UP28 I bought it as a kit off eBay that came with a 1lt tank and switch but just had a look on evil bay and couldn't see the kit, I also fitted a Protek VT1 tank as Harv said so I had extra capacity, I run it as a stand alone and seems to be ok.

The really big improvement I made was doing the VT caliper upgrade and on the weekend I also found that the adjustable pin on the pushrod in the booster was set too long and pushing the piston in the master, so this may have been partial problem I had with the brakes being constatly on (maybe)

Neil

Harv · Post by **Harv** » Mon Mar 21, 2022 11:58 am

FireKraka wrote: Mon Mar 21, 2022 11:21 am The really big improvement I made was doing the VT caliper upgrade and on the weekend I also found that the adjustable pin on the pushrod in the booster was set too long and pushing the piston in the master, so this may have been partial problem I had with the brakes being constatly on (maybe)

Some master cylinders require a preload (typically a few mm). The XA/B/C &*#@ one that I am using does. Others don't.

Cheers,
Harv

EK283 · Post by **EK283** » Mon Mar 21, 2022 2:00 pm

Thanks for all the replies guys,

Now this is funny or sad depends on which way you take it, but i was mucking around with some fuel lines today because my engineer asked where my return goes from the fuel injection, i said back to the tank not realising that it is not allowed to go to the boot area without detailed testing. This is so if a fuel hose lets go the boot wont fill up and kaboom !!!

Anyway that job done and i started the car up to test for leaks, all good ! Then i thought I should do another vacuum test properly throughout the rev range etc. So armed with my gauge i pulled the vacuum line with the check valve off whilst the engine was running and nothing, no engine rev change WTF ??????
So i stare and wonder and yes its true the bloody chinkanese check valve has so much resistance on it it wont let the vacuum suck on the booster until it it is high enough to do so.
Scratching my head I check the gemini valve and its clear as a bell, another in my spares Fraud and its the same !!!!! I have a chuckle and wonder why this valve is so hard to suck through, Its Chinese what should i expect but as usual I am greatly disappointed !!!

: IMG_1203.JPG (4.59 MiB) Viewed 798 times

From left to right Fraud no resistance, Gemini no resistance, Chinkanese cheek sucking in resistance !!!
8 inch Booster still fits ok with about an inch clearance to the rocker cover.

: IMG_1204.JPG (4.78 MiB) Viewed 798 times

So I am going to do another road test before I lash out for a pump but at this stage my idle is 15HG, 1000rpm 18HG and deacceleration is 20HG. This should be ok for a booster but we will see, now that i'm getting full vacuum to the diaphragms i have some confidence !!!!!

Greg

Errol62 · Post by **Errol62** » Mon Mar 21, 2022 3:00 pm

The modifier path is a windey one Greg 8 )

FB ute fixer upper, EK van on rotisserie

FireKraka · Post by **FireKraka** » Tue Mar 22, 2022 10:39 am

Hey Greg I also found that the check valve on my Chinese booster was stuffed it gave no resistance at all didn't mater if you sucked or blew made no difference I had one in an old commodore booster so swapped that in

EK283 · Post by **EK283** » Fri Mar 25, 2022 5:03 pm

I took the car for a quick spin today and the good news is brakes work perfectly !!

So the final combination is , dual diaphragm 8 inch booster with a XB frad master, HQ steel callipers and rotors and 10 inch rear drums.

To be honest it pulls up effortlessly and I'm going to say better than 2 of my modern day cars !!!

I did 6 hard stops in a row and no hard pedal or even a hint of no booster, the only real worry I have is how long will the chinkanese parts last ??

Any way a couple of small things to do and I'm booking in again hopefully for a tick of approval and rego.

Happy days ahead i hope ???

Regards Greg

In the Shed · Post by **In the Shed** » Fri Mar 25, 2022 6:06 pm

Getting close

Errol62 · Post by **Errol62** » Fri Mar 25, 2022 6:55 pm

That must feel good the brakes are so good

FB ute fixer upper, EK van on rotisserie

EK283 · Post by **EK283** » Mon Apr 04, 2022 8:52 am

Last job for the engineer and then a re book with fingers crossed !!!

Bought a new master because the one I have is an original PBR and I didn't want to ruin it and also I now have a spare

Bought some sight glass, screw in and a tap, $40 all together.

Drilled, tapped and inserted.

: IMG_1274.JPG (5.81 MiB) Viewed 667 times

: IMG_1276.JPG (4.66 MiB) Viewed 667 times

: IMG_1280.JPG (6.7 MiB) Viewed 667 times

Hey I've just realised I have a rare NASCO double diamond dot Brake Master !!!!

Install today and re bleed the brakes then engineer again.

Greg

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