1988 Corvette Rear Wheel Bearing replacement –

I got the information from several posts on the the Corvette Forum  http://forums.corvetteforum.com/c4-tech-performance-48/?id=48  ,  from 101 Projects for the Corvette by Richard Newton  and from a friend, Rod, who has done the job himself.(Rod’s comments in italics)

There are plenty of warnings on the Corvette Forum NOT to buy cheap Chinese bearings.

I bought the bearings from Corvette Recycling  http://www.corvetterecycling.com/ in 2009 for us$356

Each side has a steel, teflon coated washer which is important to prevent noises. I found them at Corvette Central, us$35 inc shipping.

Here are my notes to Steve the owner/mechanic at Advanced Automotive Cairns, who looks after my vette really well -

Hi Steve,

Have supplied two new washers (see diagram) these are very important and stop a click noise – they must go the right way round and should fit flush with the hub- note how the old ones are fitted. Please use plenty of anti seize grease on splines and washers.

Some people remove the halfshaft, some leave it in place and get at the torx bolts with a 6″ or 12″ extension- The torx bolts need to be clean and if stuck can be heated carefully.

Taking shaft out makes access easier but more work. Problem is torx bolts are often frozen in and you have a problem getting the right leverage around the shaft.  Spray with WD40 before. Make sure torx bolt heads clean first so no slip.

Note: Steve left the halfshaft in place, but says he needed several extensions to get access and he used a NEW torx bit.

Make sure you wire brush the splines on the yoke clean

PROCEDURE:

1 Remove ABS sensor to prevent damage

2 Undo 2 bolts holding caliper to knuckle ( spindle / upright / whatever you want to call it )  and tie caliper assembly out of the way.

3 remove brake rotor

4 remove cotter pin (36mm) and washer from brake assembly
Hub nut is 36mm; should be tight , very f’ing tight.

5 Mark half shaft so it can be replaced same position

6 Remove UJ straps and drop half shaft
Don’t always work like that. Shaft will not necessarily drop out without removing other suspension parts ( bottom chamber arm ) so knuckle can be levered out to gain clearance room for uni cap to clear side yoke

7. Undo three 55mm torx bolts that hold bearing in

Refit
1 Tighten torx bolts to 66ftlbs

2 Fit new thin Teflon coated washers on splined area of half shaft
Must fit up flush to the inside. If there is a gap they are on backwards
Put a little grease on both sides. Washers should fit directly against the bearing

3 Install halfshaft, leave caps off

4 Place calliper bracket and bearing on rear spindle- lube splines with anti seize grease

5 Install spindle washer and nut

6 Tighten nut to 185-192 Ft/Lbs – get it tight on car and finish when wheels on ground

7 Replace nut retainer and fit

8 Replace brake rotor

9 Install calliper

10 Install abs sensor new cotter pin

Split View Diagram – Teflon Washer arrowed- (NOTE Main nut Torque setting incorrect here)

While my old windscreen was removed, I took the opportunity to have the window frame sandblasted back to bare metal and repainted. Then I painted over the new black paint with Xtroll, a heavy duty rust preventative and converter which appears similar to the US POR15.

It set hard in a few hours and made the black paint look very shiny. I think it will be an excellent rust preventer because it is a thick semi hard coat and the drips were very hard to remove (with Kerosene).

I had many replies to my post on the Corvette forum about which weatherstip glue to use for the weatherstrip.

Aircon – some interesting facts

I live in the tropics so the aircon is very important, I now have constant vent temps of 6.6C to 7.7C while outside road temps show 33C , I’ve learnt a few things while making my aircon efficient,  here’s what I’ve discovered.

My vette was converted to Right Hand Drive and at the same time to R134 gas . It has the C68 climate control.

The first thing I did to maximise the efficiency of the aircon was to disconnect the heater hoses. I have never needed the heater in Cairns.

I was disappointed with the airflow from the blower – I fitted a new blower and it drew less amps than the old blower, but the airflow was EXACTLY the same – about half what’s needed. I have heard that newer Japanese blowers move more air but haven’t found a suitable one yet. Auto electricians tell me I’m looking for more speed, which makes sense.

I took the dash apart – found a beer bottle top, half blocking a disconnected air vent tube, and a few other problems like that. All legacies from the RH Drive conversion. The Air box is moved from RH to LH side during the conversion and also inverted. I cleaned out the evaporator because when new, they have a sheet of foam in front of them and this melts/deteriorates over time, especially in hot climates. I fixed several air leaks from poorly sealed joins etc.

I fitted a dual digital thermometer, from Dick Smith Electronics, so I could measure the centre vent temperature and the cabin temps – and get an accurate view of what was happening.

There is an adjustable inline screw, beside the evaporator box, that sets the low pressure going into the evaporator. In my attempts to get colder air, I turned it down very low, (anticlockwise,1/2 turn) but the evaporator iced up. The signs were the vent temps going from a nice 9 or 10C and rising to past 22C – always fixable by leaving the fan on and turning A/C off so it could thaw out. I turned it the other way (1/2 turn clockwise) and the vent temps were not cold enough- 12 – 13C, and still the evaporator eventually iced up, sometimes after an hours driving.

I also found that when the car was parked and hot, upon restarting, hot air would blow from the vent until the car was moving – the inline coolant fan switch was not working – it should turn the coolant fan on when the aircon is turned on, so that air flows across the accumulator, in front of the radiator. I fitted a manual switch to turn the fan on and this solved that problem until I replaced the switch.

Arrow points to the switch which is in the gas line running along between the radiator and the front of the engine and

I had the gas checked to make sure the pressure was correct.

The aircon box is in two halves and I found some major leaks on the engine side of the firewall, where the aircon box joins had split open. I also found two oblong section air tubes under the dash, venting air into the dash cavity – if they were a bit longer, that air might have reached the foot well, but the size of the pipe was too extravagant for the amount of moving air. First priority, for me, is to blow cool air on chest and face – then onto feet. So I partially blocked them –I also found the heater door was not completely closed.

After I sealed these significant air leaks, the blower on ‘full’ was now giving maybe 7 out of 10 airflow. I then discovered that this had cured the frozen evaporator problem and stopped it icing up.

By this stage I saw the incredible vent temps of between 6.6 and 7.7C, and no icing up of the evaporator. Aircon mechanics are happy to set the vent temps at 10C so this is a significant achievement. I can only assume that fixing the air leaks and closing the heater door increased the airflow through the evaporator.

When the vette has been parked in the sun, it takes over 30 minutes to cool it down, because the fan doesn’t shift enough air, so I’m still on the lookout for a better fan

Two other things I have discovered are – if the blower only blows full speed, an inline fuse, under the hood, near the bulkhead has blown – I replaced mine with a 15 amp fuse and have had no further trouble.

One day the blower was stuck on, even with the ignition key out – the blower module had failed.

On LH drive cars, the module is on top of the aircon box, so on RH drive cars it’s on the bottom and not so easy to replace, with the chassis close underneath it.

This is the view when laying on the ground looking up at it!!!

I got some great help from the Corvette Forum, including two NSW Aussie vette owners – rodj and Aussie Vet .

I’d like to say a very special THANK-YOU to the Corvette GURU on airconditioning, whose username on the Corvette Forum is SunCR. Many many thanks Bill, for your hours of help as we’ve worked through my aircon system .

To sum up – check the gas pressure. Clean the evaporator which probably is clogged with foam that has deteriorated over time, make sure the radiator fan comes on when the aircon is turned on. Make sure the heater door closes properly- that’s VERY IMPORTANT. Look for air leaks. Have the adjustable screw correctly adjusted.

When I first got my Corvette in 2003, the engine was very dirty.

I did my best to clean it with degreaser and brushes first. I was very unhappy with the result – the black plastic parts looked faded and seemed to have a transparent skin that was peeling off in places – it looked bad.

 I heard about this way of regaining the black on faded parts on the Corvette Forum, this involves spraying a warm engine with Armourall Tyre Spray.

 A few people said it worked so I did a small test area. It made the plastic go black and shiny and it look so much better. I sprayed everywhere in the engine bay including inside the hood. It made a huge difference and lasts and lasts – I’ve never seen anything revert to the grey white powdery look – I was amazed at how good and easily it fixed everything.

After Using Armor All -

Note: As part of the original cleaning up of the engine and maintenance, I also replaced the Rocker covers and shockabsorbers, painted the exhaust manifolds etc. Note the vaccum booster, the AIR diverter box, the inlet manifold hose, top of radiator -  after the spray they came up like new!

I was concerned that everywhere would turn into a gooey sticky mess but that’s not the case – I now spray the wheel wells, under the bonnet – everywhere – remember not to spray on Serpentine belt as it’s slippery.

UPDATE – I’ve been sprucing up the engine compartment with Armorall for a few years now. I can definitely say it does not harm anything, there’s no noticeable build up, it’s not sticky or attracts dust. It’s just a fantastically easy way to keep the engine looking good.

Instructions -
Wash engine for the first time application and get everything as clean as you can, spray onto a warm engine close the hood and wait 20 minutes – TOO EASY – they’re bound to make it illegal !!

How to replace UJ’s WITHOUT removing C Beam

The factory service manual states that the C Beam must be removed to replace the universal joints on the propellor shaft. Some members of the Corvette Forum said that this was true, BUT a few said it was possible to do it and NOT disturb the C Beam – possibly this only applies to Auto trans like mine?

After some research I got confirmation from forum member rodj and some clear instructions on how to do this. The advantages of not removing the C beam is that it reduces the time of the job, possibly by a few hours! and there is no chance that the C beam will not be put back properly, nuts not tight enough etc because it is a well known PITA to work with due to lack of room – it has to be wrangled in and out and also very hard to get at the front nuts which are above the beam.

The first part of this info concentrates on the prop shaft UJ’s, and then scorp508 has given permission for me to host his excellent write up on replacing the halfshaft UJ’s

Below is a copy of my write up for the mechanic who did the job for me, and after that scorp508’s tech tip with photo’s. The mechanic reported that my FAQ sheet was a huge help to him and confirmed that everything was correct.

NOTE – Driveshaft and halfshafts are made from soft aluminium and easily damaged.

All nuts/bolts are Metric.

Factory Manual and Haynes Manual supplied

Hood release under LEFT HAND side of dash,

This fact sheet is compiled from info received from other Corvette owners who have done the U/J replacement job themselves and is vouched for by several owners who have followed these or similar instructions.

The manual says to remove the Driveline Support Beam (C Beam) but this is NOT RECOMMENDED – all reports say this is a tricky job –

“The C beam is a PITA to remove if you have never seen one before. You need small hands to get up side of tunnel and hold open ender on top of beam while undoing bolts underneath.Then you have to get it out which is a work of art in itself. Replacement also involves measuring alignement, R/R just for the C beam can take hours.”

The instructions for Driveshaft removal came from Rod in Sydney who has done the job many times and it can come out in as little as 10 mins.

REMOVE DRIVESHAFT FIRST so that brakes can lock diff to allow easy undoing of rear UJ Straps on diff.

Mark the drive shaft so you can install it back in the same position to keep the correct balance.

DRIVE SHAFT REMOVAL –

Hoist Car

Drop exhaust

Undo bolts holding uni to diff,  You may need the diff locked in order to crack the strap bolts loose , you can only really work on one bolt at a time and then need to rotate.

Use a long 1/4 drive ext for better access

MANIPULATE DRIVESHAFT OUT –

Driveshaft will  move foward on the trans yoke allowing you to get rear uni’s caps off the diff yoke. Need trans out of gear and handbrake off so you can rotate yoke to best position to get caps out .

Take rubber hammer, and tap the drive shaft FORWARD into the transmission, angle the drive shaft so its above the handbrake cable that goes horizontally across the car.

Take the rubber hammer, and tap the drive shaft out of the transmission.

DS will slide back beside diff head over handbrake cable enough for the  yoke to come free from trans.

The handbrake cable can be undone if needed, but I don’t recommend it because it’s 20 years old and may be brittle and break. (It’s made to come apart at the clip about in the middle)

May wish to have a catch pan under the rear of the tailshaft to keep transmission fluid from leaking on your shop floor

DS can then be moved foward to clear handbrake cable and down.

Check rear trans seal while you have DS out , cheap insurance against leaks.

Remove old UJ’s and fit Spicer K5 -13 XRHD

HALFSHAFT UJ’S

Below is a link to the excellent write up by scorp508, with clear photo’s for the halfshaft UJ replacement. I found a post by him, after he had done his UJ’s which showed there was one alteration to the way he showed the removal. Instead of undoing the camber strut at the inbord adjustment end, he undid it at the outer end, which prevents the camber from being altered and saves having a rear wheel alignement.

Click
HERE for a link to scorps write up for the halfshaft UJ’s. (Opens in a new window)

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C4 Corvette Courtesy Lights Dimmer Module

Here’s a picture of the circuit board, heatsink removed -

If your courtsey lights don’t go on when either door is opened, the dimmer module may have failed.

Signs that the module has failed are -

The hatch door switches don’t work, but the console hatch switch does.

The interior lights come on by turning the light switch but not when you open the door, or they may stay on all the time.

Test by grounding the thick white wire at the module – door hatch switches should work.

Check the black wire is connected to ground. If so, then dimmer module is not connecting these two wires together and making a circuit when the doors open.

Check that the dimmer is receiving a ground at the yellow wire when either door is open. (This yellow wire may be thin white for some years.)

The dimmer module is no longer available as a replacement part. Also one of the main electronic components is no longer available.

My module was fixed by an electronics expert who examined the circuit and found a suitable replacement part.

Here is all the info I have – I’ve listed most of the parts, in case it can help anyone else.

Location:

The dimmer module is in a small 2"x2"x.5" black plastic box, taped to the wiring loom behind the centre dash. (In my converted to Right Hand Drive vette, the module was midway behind the passenger crash pad.)

The module is wired -

"A" White wire goes to all of the lamps and supplies negative

"B" Black is Ground. Shorting White to Black will turn the lights on.

"C" Pink/White is 12 volts from the Ctsy/Clk fuse which is hot all of the time.

"D" 2 Yellow wires – (these may be white for some years) come from the Door switches. The switches close when the door is open and provides a ground on the Yellow (or white) wire/wires depending on what door is open.

"E" is the Reset signal used by the Delay Module to turn the Module off when you turn the ignition key to on. So the lights go off.

Here’s the circuit diagram in the GM Manual for my 88 Corvette.

The dimmer module is thin and the circuit is not very complicated -

The metal piece is a heatsink on a large transistor.

The Transistor is in a TO 220 case, and in mine tested faulty.

It’s no longer available.

Mine was replaced with an MJE 3055 and it worked again!!!!

I suspect that it fails because it takes the most heat/power. The heatsink begins to get warm to the touch within a few seconds.

A test of the amp draw showed my courtesy lights draw 2.8 amps and pressing the rear hatch release increased the draw momentarily to somewhere between 3 and 4 amps.

All parts in the module from my 1988 Coupe look brand new.

Here’s a parts list – only one signal diode was unreadable.

3 parts were not given a number so I’ve called them U (Unknown) One, Two, Three

Here is a diagram drawn up to work out how the circuit works -

A – to Lamps

B – To Battery negative

C – To Battery positive

D – To door switches ( a negative volts signal here will turn lights on, including a 15 seconds delay after low is removed)

E – to positive of dash lights ( a positive voltage signal here will turn lights off)

I hope the information here will help someone else repair their module – mine has been working since August 2005.

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