StevenPH wrote:I unplugged the vacuum hose, drove ten miles and the brakes seemed to do much better. No smells, no sluggishness. Does this point to a new vacuum pump? New booster?
I'd say booster... a bad pump might have the opposite effect - poor braking.
StevenPH wrote:On a side note - after the the 10 mile test drive i was inspecting the area and there was a substantial oil leak - it looked as if oil was coming up out of the dipstick, running down the dipstick sheath and all over below it. Probably a couple tablespoons of oil in ten miles. It definitely wasn't there when i left. Could that have been related to pulling out the vacuum hose? I detached it up were it connects to the vacuum booster, and there was no oil around the pump itself. I've never had a leak there before, so it seems far too coincidental to be unrelated to the vacuum hose.
I would test again, ensuring the hose is plugged while it is disconnected from the booster.
StevenPH wrote:If that weren't enough - i've also noticed a slight shimmy in the steering wheel above 65 mph. Anyone have thoughts on how that might be related?
I'd guess unrelated.
Have a nice day.
'91 Jetta ECOdiesel TD - clean & complete (less motor/tranny) for sale
The oil leak is definitely due to the vacuum hose - it stopped when i reattached it.
I think i'm going to take it in for a full diagnostics check - it's looking like some of these issues are related to the head gasket/blowby issues ive been having, and that's getting slightly out of my league at this point. Hopefully the brake issue is unrelated, but i'll have them diagnose it before i start replacing those pricey parts.
Until i can get it in - would i be causing additional harm to the engine to continue to drive for the day with the vacuum hose disconnected? It actually drives better than it ever has with it off - it has more power and less exhaust smoke than ever, and the engine stays cooler than usual. I'm wondering if this hasn't been an issue under the surface for as long as i've owned the car (1 year). I've always had poor fuel economy (under 45mph) and sluggish acceleration compared to other vw diesels i've driven.
If an operating vacuum pump was open to atmosphere, wouldn't it add some pressure to the sump, especially if the top vent on the cam cover a bit blocked, in addition to the ring blowby?
"I'm not here to help... I'm here to Pro-Volke"
Be like meeee...Drive a Quantum TD
...The best work-horse after the cart...
Quantae grow on you...but Rabbits are like roses...
... girls like em ;o)
Only one Darwin, Einstein, Poe and Verne.
That is why if you listen, you will learn:
From the one and only Quantum-man,
Who sees the worms from outside of the can.
7 Quantae in 20 years; 4 dead and 3 TD's still alive [2 wagons & 1 fastback] oh and a GTD )
yes you can re-ring with the engine in the car. Remove the head and oil pan, etc. and you can unbolt rod bolts and pull the pistons out. Assuming it does not need a rebore you can hone and replace the rings (and rod bearings if necessary - I always do)
Today i was driving around collecting parts and tools in preparation to get inside and replace some axles, wheel bearings, head gasket and piston rings in order to try solve this dragging brake/blowby issue, and suddenly my clutch pedal stops releasing. Id push it to the floor, shift (suddenly very roughly) and when i took my foot off it would return an inch or two then stop. I could lift it with my foot but it wouldn't come up on it's own.
I pulled off the road and basically it felt like the cable was too loose. So when the pedal depressed it wasn't fully disengaging the clutch (it felt like, at least, i know little to nothing about transmissions). I have a self adjusting cable, but it felt like it needed adjustment. So i took cable off of the clutch control arm (i think that's what it's called) and stuck a few washers i had in the glove box under the rubber gasket to shim it up about a centimeter.
After that it worked fine again. Drove home with no problems.
A few questions -
Am i at risk of damaging anything if i shimmed it up too far? Would there be any symptoms if it was?
Immediately i thought this meant that my problems with my brakes have to come from inside the transmission - it couldn't be a coincidence. But after inspecting everything for heat it still doesn't seem that way. The tranny was no hotter than usual, neither were both axles. The brake calipers and hub area was still the hottest by far. No leaking in the tranny, correct levels of clean gear oil. No slipping, grinding, or anything in the transmission since i've owned the car, and the previous owner was a VW mechanic and put the tranny in a few months before he sold it to me.
Has anyone else had this happen to them? Could it be so simple as it seems? Is there be a way to manually adjust the "self" adjusting cable to the proper length and get rid of the washers?
Sometimes the firewall, where the cable goes through, can collapse.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
What do you all think about a master cylinder leaking into the vacuum booster as a cause for all of this? I just pulled the MC and noticed moisture inside the booster - using a spray bottle top with the hose down inside the booster I then pulled almost a quart of dirty old brake fluid out of the bottom of the booster! I could believe how much was in there. Brown, almost black fluid.
Sorry, I sold my 91 NA and have been off line for a few years.. but I know this problem and solution.
The person that said the brake booster rod needs to be adjusted is the winner.
The rod should have at least 1 mm free play between it and the master cylinder, and the rod is adjustable.
it takes a series of measurements with a precision device:
1. with master cylinder removed, the distance from the face of the booster to the tip of the rod
2. distance from the rear of the master cylinder to the center of the piston cup (depth)
3. distance from the "shoulder" of the MC flange to the rear of the MC.
Do the math and adjust the rod until you have at least 1 mm free play at rest.
When there is no gap, the engine compartment temp raises until the fluid expands, and self applied the brakes.
the piston is now a mm or 2 past the pressure relief hole in the MC that allows the brakes to retract, and the brake stays applied on the right front side, due to the circuit layout..
BTDT. Drove me mad figuring it out.
Take a good look at the MC before replacing it. It may have already been replaced, and the fluid is still there from the last, failed MC.
I turned in a near new BOSCH MC as a core when I replaced mine.. then found out that the one I just got rid of listed for over 200 at the dealers, and wasn't available at my FLAPS.. and wasn't the problem after all.
A whole series of hard earned lessons.. including replacing the MC, front calipers, pads, etc, then pulling a booster from a junkyard, and only then figuring out that it was a simple (relatively) adjustment.
And yes, the rod was still adjustable up to 1991, at least.
I think I posted a writeup on this a few years ago..
Yes that's what I was referring to in my August 9 post. That was definitely the problem on the old 51 Chevy pickup. Would be nice if that was the problem here, would be an easy fix. Can't hurt to try if in fact the rod is adjustable.
Yup i think you have it. Just drained the booster of a quart of fluid and put in a new MC, got back on the highway this morning after putting in new rings and presto it happened again. I've also been finding the front ride side to apply slightly more than the left, so it would seem the rod is the culprit.
When i put in the MC i did see the adjustable rod in the booster - and now am kicking myself for not making those measurements and adjustments when i had it open.
I'll see what i can do after work today and let you all know how it works out. but that has to be the problem.
See if you can remove the two nuts holding the MC and just pull the MC out of the way without disconnecting the brake lines..
they will bend a bit, but it "should" work.
Have a friend push the brake pedal to the floor (or wedge a stick in between the pedal and the seat if you don't have any friends.. or they're not available..) to push the rod out for adjustment.. after you've made your measurements.
I think I used needle nosed vice grips to make the adjustment.
you have to grab the adjustable shaft at 2 places, if memory serves.
I ended up just pulling the lines - I've gotten pretty quick at it. Had to pull out the rod too, I needed to get it in a vice clamp to get the bolt loose. From what I could determine without extremely precise measuring tools it was right about even with the inside of the MC plunger. I shortened it up, pressed it in with that holding disc thing, and bled the brakes. The brake pedal now depresses way further before engaging - but braking power is still strong. I have a feeling I went further than I had too - but I want to leave it for a few days to make sure the problem is solved. Then I may go back in and lengthen the rod until its just where I want it.
Ill let you know how it turns out - thanks for your post, this has been a long haul!
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