Brake Booster to Master Cylinder Shims

[Davidcu]

Has anyone used shims between their Brake Booster and Master Cylinder on a VW Bus (76)? When I put my new MC on it had a gap between it and the Brake Booster where it met resistance and i had to crank down the MC to the BB. The push rod on the BB is not adjustable. It is one that has the rounded head that can be pulled off the end and a spacer put on to lenghten. But what if it is too long. Now I am assuming I may need to shim the two together so that there is no resistance when I tighten down the bolts. Anyways. How do you shim these two together and still insure that the rubber seal is effective on the MC? Hope this makes sense.

[busdaddy]

[Davidcu]

Thanks, I guess another way to do it is just remove the rounded tip from the push rod coming out of the Power Boster and then the MC fits flush with no resistance but what does that do to the inside of the MC when it makes contact. You would think that they would make different sized tips for the rod or just make them all adjustable. Interesting.

[Davidcu]

By the way, I got my copy of "The Bus" yeasterday. Watched it last night and it was great!!!!!!

[Davidcu]

Not sure of the total solution yet. Will hard bleed the brakes this weekend. (again). I would think if the push rod of the BB was too far out then I would be having a problem with the brakes locking up or partially engaged when driving but my problem has been not enought brake pedal. It is rather soft until about half way to the floor then will stop the bus but you have to really push hard to get results. Works even better if I pump them twice when stopping. Maybe I should try to put a couple of spacers on the rod tip and see if it works better. Maybe I am not getting a full stroke on the MC because the rod is too short? Am I making sense or just overthinking this again.

[kreemoweet]

You need the rounded tip on the booster push rod, it matches the socket in the M/C piston. If you can't figure
out a way to shorten the push rod (by filing/grinding?), I don't see why a gasket (or stack of gaskets) couldn't
be made to seal the booster-to-M/C joint. All kinds of gasket materials are readily available at auto parts and
hardware stores. 1/4" thick rubber gasket mat'l from the plumbing dept. might work. VW exhaust gaskets will
work if you enlarge the ID a bit

Just reread your post: I thought you are saying you had found your push rod was too long? And then you wonder
if it's too short? Huh? Your stroke is not determined or limited by the length of the pushrod. It's sounding like one
of your brake circuits is not functional, possibly due to an internal leak in the M/C.
_________________
'67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

Stop dead photo links! Post your photos to The Samba Gallery!

[Desertbusman]

Is your pedal pushrod adjusted per the book?
_________________
71 Superbug
71 Westy

[Synapse]

I agree with Kreemoweet, I don't quite understand what your referring to from your posts. Do you think you take some photos for us?

Take a look at my post below, I posted some pictures for referrence.

http://www.thesamba.com/vw/forum/viewtopic.php?p=6059713&highlight=#6059713

[germansupplyscott]

what kind of master cylinder?
_________________
SL

[Davidcu]

Hey Scott thanks for the response. Here is what I have. I am new to the VW Bus restoration business although I have restored many many GM Muscle cars over the years. I have been learning a lot about German Engineering and the quality of compared to the American GM experience that I am quite good at through many years of putting those beasts back together. Now I am finally working with real engineering that the Germans have obviously put into these clasic busses. Hence quality parts and percise mechanics have become the standard with my rebuild.

The brakes were working on the bus but as usual everything looked really whipped and I decided to just replace/rebuild everything. Not knowing anything about the parts suppliers I have been experimenting with about six of them comparing quality - shipping times and return policies. What I have found is a priority list in Quality - Proiper fit - deliverability - return policy order. The list is the best to the not so best order as follows:

[Davidcu]

My order is:

GermanSupply - Canada
WagonsWest - Oregon
GoWesty
Wolfsburg
BusDepot
Cip1

I have ordered from all of them. I try to order only vw-german parts but am not always assured that is what I get. The Master cylinder was ordered from Wolfsburg part # 211-611-021-AA whci was supposed to be the German made. It didn't lookexactly like their picture but more like the one you have on your WEB site part # 211-611-021-AAGR and it cost me $179. I am assuming it is the good one. I tested it out of the box by pushing the rod on the end and there was air blown out the two holes where you attach the front and rear brake lines and I do get brake pedal but it could be better and has to be pumped twice sometines to get better pressure. I am bleding again this weekend.

[SGKent]

the pushrod may be out of the socket on either end and catching on the ledge. The adjustment on a late bay is not made with the pushrod length but rather the shaft that pushes it. When we replaced our MC the MC was an ATE and it fit perfect with no changes. I think something is wrong so stop right now and figure what it is.

[Davidcu]

As for the Brake Booster. I had Bus Depot send it to a company in dallas Texas anbd it was rebuilt. By the way when I pulled the old MC off the Brake Booster was full of brake fluid so it definately was a bad MC. Having said all that. when i reinstalled the new MC the instructions said if it didn't fit flush with the BB without resistance from the push rod in the MC then the pushrod in the BB should be adjusted. Well It almost did but was about 1/8 inch from fitting flush when it met resistance. I just tightened it down with the bolts and since it wasn't locking up the rear brakes I assumed it was OK. That was what all the previous blogging was about. I then readjusted the rear brakes tight and am getting brakes. Just not as good as I should so I am looking at how to get all the air out of the lines. I replaced all the rubber brake hoses so they should be good to go. Not sure if a bad proportioning valve would cause a pressure issue but didn't seem to be a problem before but could be now. I will have you rebuild it later.

[Davidcu]

By the way, I was extemely impressed with the bolgs about your Brake line kits and how you remeasured and correded the lengths in your kits. I am getting ready to order one of them just to coplete the entire restoration and feel confident that your products are the best quality and fit.

having said all of this I have to say after 6 months of rebuilding and sapling products GermanSuppy by far has the best quality and fit of allthat I have ordered from. Great job guys. Now if I can just get these brakes working safely I can start looking at a rebuild to the engine which seems to have a noise coming from the hydrolic lifters and with the speedo turning over many years ago I suspect a rebuild is in order, copression isn't bad though.

I have also rebuilt all the fuel injection (Thanks fo rthe perfect parts Scott) and have learned alot about vintage VW FJ.

[Davidcu]

Thanks for the reply gskent. I didn't understnad your initial response. Are you talking about the push rod on the BB not in the femal portion of the MC and hitting the eadge of the BB? Also are you saying that if the rod coming off the brake pedal going into the BB. If that is out of adjustment it will make the push rod on the MC of the BB stick out too far and cause problems? Sorry I sometines are a little confuesd about terminology.

[Davidcu]

Just re-read my previous post and it didn't make sense. The last part should say. If my brake pedal connection to the pushrom going into the front of the BB is out of aleignment it will cause the little rod coming out of the back of the BB to stick out too far.

[Desertbusman]

Refer to your service manual to correctly adjust the pedal pushrod. Likewise bleed the brakes per the manual. VW's are not GM's and many things are done differently.
_________________
71 Superbug
71 Westy

[Davidcu]

Thanks desert bushman I will go over the pushrods from the brake re adjusted per Bentley and also use their bleeding sequence and see what happens.

[Davidcu]

OKI , read the Bentlys manual again last night and from what it is saying on the 76 bus is if the pushrod adjustment from the brake pedal to the front of the Brake Booster is adjusted correctly there should be no need to adjust the rod going from the rear of the BB into the Master Cylinder as that should be set at the factory or re-build shop. I am not getting any lock up on the brakes or high pedal so must be no pre load problems with the MC and rod going into it and shuttling off the fluid flow pre-maturely. My final push will be to bleed again and again. If all else fails I will be limping O-Hanna (her name which is The Family in Hawaiian) into my local VW specialist here in Portland (Chucks Volks Works) great guys and they do excellent work. That is a last resort though as they will most likely be telling me I did something simple and stupid and will take some of my parts money from me . Thanks all for your great input. You boys rock!

[SGKent]