1977 VW Microbus - type 2 body - brake and possible valve problems

Hello folks, I am a newby, so be patient. I just purchased my first VW microbus. The engine was not running, but everything seemed to be in pretty good working order, or at least could be fixed. After a couple of hours of rewiring the engine compartment components, (the previous owners mechanic disconnected all the wiring and just left it that way), replacing the fuel, and the bus fired right up. It had not ran for several months. The previous owners mechanic told him that the reason the bus could not drive up the hill in front of his house was that the valves were shot and a valve job was needed. However, I am not 100% sure how accurate this explanation was. The ignition wire to the coil had a connector that would barely stay on the coil's post. I think this may have been vibrating and causing the loss of ignition. It is kind of a wild thought, but still a possibility. The other thing that bothered me about the mechanic's explanation was that the engine was just 4 months into service. The previous owner had paid this same mechanic to replace the engine, which he did with a rebuilt motor. Seems strange that valves would burn in 4 months. So after firing up the engine, I took the bus for a quick spin. It seemed to have plenty of power and acceleration for a single carborator 1600cc motor. Yes, it is a 1600cc engine, even though the books show that this vehicle should have a 2000cc engine. So upon returning to my house, I pulled out the compression tester and did a compression test on all 4 cylinders. They all came in at about 60-70 psi. This seems extremely low, as the book says they should be around

110 to 140 psi. I did the procedure by the book. Rolled the engine over with no plugs in the engine, tester in one cyl at a time and the carborator wide open to allow maximum air on the intake. So I then pulled the valve covers off to check the gaps when each cylinder was at its power stroke, sure enough the gap between the rocker and the valve was within specifications. So this would indicate that the valves are burnt, but the strange thing is that they all fell within a 1 to 2 psi of each other and the fact that the engine was just rebuilt.

So question 1: Does 60 to 70 PSI make since? Seems very low, but maybe I am not thinking of something.

Now for the brake problem. So in my first little run, I noticed that I had no brakes except for the list inch or two of the brakes throw. So I pulled the tires off, , inspected the brakes. They were in good shape, but I decided to replace the pads and turn the rotors. While going through that process, I bled the brakes. The resevior was all but empty, if it had any fluid in it, it was not decernable. So I filled up the resevior and started the bleeding process. What came out was extremely bad, it was dirty and so full of absorbed water that it floated on top of new brake fluid that was in my catch container. So after a ton of pumping clean fresh fluid came out. I bled each of the two ports on the front calipers. I re-assembled the brakes and took it for a quick test drive. Things were better then before BUT.... In order to get brakes, I had to pump the pedal about 10 times. Slowly pressure would build up and the brakes would work great. But as soon as I took my foot off the pedal, the pressure would go away and I would have to go through the pumping exercise again. I would normally expect this to be air in the lines, but that normally causes the brakes to be mushy, but in this case the brakes do not exist at all until several strokes have been taken. Also, if I hold my foot on the brake, the pressure does not bleed off and holds much longer. So from my basic knowledge of general brakes systems, I am suspecting one of three things may be causing this problem.

1) air in the system (my son and I bled these lines for a long enough time that this would suprize me). However, i am going to bleed them again just in case. 2) the rear brakes have not been bled, so "water" laised brake fluid in those rear brakes is causing the problem. 3) one of the pistons in the early stages of the brake system (either part of the master cyl, or one of the slaves cyl) has a leak backwards around the pistons seal. Allowing the pressure of the system to bleed by. Although I would have thought this would have caused a failure during the stoke of my foot on the pedal and not caused pumping to be required.

Question 2: have any of you experience a similiar problem with your brakes and what was the diagnoses?

Sorry for the long note. I hope it is clear enough for some possible explanations.

My son and I are absolutely in hog heaven over this bus and look forward to bringing it back to its glory days.

Thanks for you help Chuck

Reply to
Chuck Townsley
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Yes, but it was from long overdue brake star adjustment... Are you sure your shoes are almost touching the drum surfaces most of the time? Your multi-pump problem is exactly what I experience any time that I'm overdue for adjusting the pads out with the star nuts. You can check this very easily... Adjust them out to grab and see if the problem goes away... then back off each wheel's stars so that you get just a hint of contact at each wheel when you give each a spin while it is off the ground. After a good job of adjusting, my brake pedal engages with just a bit of travel and doesn't need multiple pumps.

Reply to
Red Bug

Sounds good, I will give that a try. Like I had said, I have not looked at the back brakes yet, so lord only knows what I will find back there.

A question on breaks... Do the back break grab more then the fronts? These seems backwards compared to the wear rate of front pads vs back shoes on other vehicles that I have worked on. Is this a reflection of past technology or just a simple misunderstanding on my part? The shoes are generally quite large compared to the pads, and the drums are generally quite substansive also. Which might indicate that they are doing most of the work. On the other hand, if the backs grabbed harder then the front, it seems like the back end would swing around on wet weather.

These are the kind of questions you get from a shade tree mechanic, so bear with me.

Thanks again for your suggestions. Chuck

Reply to
Chuck Townsley

Purchase the Bentley Official Manual for '68 thru '79 Type 2 Bus. You can still buy them new, or even used on eBay. Haynes has a good transporter manual too.

That said, 70 PSI is way too low for compression, although it *will* run nicely. But like the guy said, power will be poor. Plan on replacing heads real soon before the thing self-destructs.

Another issue (and this may relate to the early failure) is that the '77 tranny is geared way too low (numeric) for the 1600 engine.

When they did the transplant, did they *completely* seal the engine to the engine bay?? If not, hot air from underneath will be sucked into the fan and cooling grossly compromised. Every little hole must be sealed off.

On the brakes, figger on simply replacing *all* the components; there is no justification for re-using cylinders which have been sitting in water-contaminated fluid. Replace the hoses too; they are now over a qtr-century old and are doubtless swelled up inside.

There is a hyd pressure balancing valve for the rear brakes; it is located underneath in one of the frame rails. That may have failed (rusted) due to the water also. These brakes are vacuum assist (power); be sure the vacuum line was connected to the 1600 engine.

Good luck; that's a nice Bus but you'll have your work cut out for you. Bookmark this useful site:

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Loads of tech info...

Speedy Jim ('78 Bus)

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Reply to
Speedy Jim

I agree; there's something fishy here. It is unlikely to be bad valves, as they would not all be equally bad. I wonder if someone got the cam in wrong. You might be able to watch the valves and make sure that the intakes open about as far ahead of TDC as the exhausts open afterwards.

Old wet brake fluid will still mix perfectly easily with fresh dry fluid. I wonder if this had silicone fluid in it. DoT-5 silicone brake fluid won't mix with standard fluid and is lighter and floats on top. It generally comes out clean, however. It's good stuff when properly installed.

This does not sound like air in the lines. It sounds like you have some shoes that need to be adjusted. They just have to travel a long ways before they contact the drums.

No. Wet fluid works just as well as dry fluid, until it gets hot.

No. I agree with your last sentence, and the fact that it stays solid while you hold your foot down pretty much proves this.

Yes, your rear brake shoes need to be adjusted.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Reply to
Jim Adney

Reply to
ilambert

Thanks Jim, your suggestions are well taken. No reason for a few bucks saved, should I take a chance for brake failure. I purchased the Bentley Official Manual and it has been a huge help. I have purchased a manual for every vehicle I have owned, it just makes since. I only have two complaints about this manual, the first is it jumps around making constant reference to other areas on how to do this or that. The other is that there is no appendix at the end to point you to specific issues. For instance, to find out the compression for the cylinders, I went to the engine area, and could not find it. Well it is in the middle of the maintenance section. I am sure there is a reason, but it just doesn't make total sense to me. Now let me jump off that soap box...

Again, Jim thanks for the advice. Chuck

Reply to
Chuck Townsley

Jim and Ilambert, thanks for the input guys. I can not touch the bus until Saturday, but can't wait to test out some of the theories.

I suspected there was something wrong with the gauge also, so I took it over to my air compressor and connected it to run a check. As i veried the air pressure coming out of my regulator, the gauge messured exactly the same as the guage on the regulator.

I went out to a link

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that was posted by a previous responder last evening and read something that made me think that maybe I made a mistake in my technique. My service manual said to test with the engine cold, and throttle held wide open. But this web site said to test while the engine was hot. Hmmm, this made me wonder if the choke could have been closed, there by limiting the air intake, and giving a low, but consistant reading. Sounds a little far fetched, but maybe plausible.

Should I test it hot, or cold?

If the choke is closed, can it cut off that much air and reduce the reading?

I am just trying to look for easy solutions prior to checking the cam or lash ajustments. Especially since I have not done that before, I suspect it isn't that hard, but who knows.

Thanks again.... Chuck

Reply to
Chuck Townsley

You should check it hot. Not only because of the choke, but also because that's when all the engine parts are the right size, and the rings will have the oil film on them which makes for a better seal

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Reply to
Jim Adney

I wanted to let you all know what I have come up with from your suggestions.

The compression when tested with a warm engine and a non-leaking compression guage came up to 120PSI. So things are great there. The main problem seems to be related to a one way valve on the compression tester that was slighly loose and allowing pressure to release and not build to 120PSI. Also the motor being hot help significantly too. When tested cold with the corrected compression tester the pressure only hit between 85 and 90 PSI. So your help was right on mark.

One the second issue of the brakes. There is a slight leak in the master cylinder that is draining the reseviors. This allowed air in the system that was being held back in the rear brake systems. I have flushed the entire system, purged all air and the brakes worked fine. That is when I discovered the slight leak in the master cylinder. And putting several peices of the puzzle together, I have determined that the air in the system was caused by that leak. I have a master cylindar on order. It along with the new pads, new shoes, new wheel cylindars for the back drum brakes, all of which have been installed should solve the problem.

Thanks for your help. Chuck

Reply to
Chuck Townsley

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